Why is Philidor Defense so popular?

It’s not so popular

But you can with computer see some lines how to play Vs Philidor And you will be strong

And also you can see games of GMs and you will know some good moves

At your ELO.... You don't know what is or isn't passive... (NOTE! A TITLED PLAYER COULD SAY THE SAME TO ME!)

Point being..... don't buy into what the patzers say about 99% of the things being said here.

A defensive player, who tends waits and counter attacks after seeing a flaw in the opponent's attack or development... Then the Philidor is a dangerous opening to play against.

In this era of having to win every game at a OTB tournament the club player tends to ignore openings like the Philidor, the Petroff, The Queens Gambit Decline (Lasker's Defense, The Orthodox, etc) because they read in a book they are drawish ...

But the books don't tell you why they are... They are drawish because they inherently offer Black a lot of defensive resources. At GM level, White to get any advantage has to skirt that fine line of aggressive chess and over pressing... That's hard to do... so the games gravitate to draws. Normal players... i.e. Club players, we don't play with the mastery of a GM, we make mistakes, over press, we error in our calculations, play endgames poorly...

At the Club level openings like the Philidor are hardly ever passive

For years it was regarded as inferior and the discarded line. Over time people forgot that and decided to try it again. That did not change the fact that it is inferior to far better opening lines.

It's inferior to other choices (such as 2. ... Nc6) only in the sense that Black's road to equality will be a bit longer and a bit rockier.

All sound openings... ALL sound openings... lead eventually to roughly balanced positions.

That's what makes them "sound" openings.

The major difference between them is how hard Black will need to struggle for that equality.

the philidor position, be it the hanham structure or the exchange variation has a lot of latent energy. Black's queenside has a lot of counterplay waiting to be unleashed and usually attempts to slow it down creates other holes black can exploit.

it is only as passive as your capacity to create counterplay. Here is for example one of the critical lines where white plays aggressively.

does this look passive to you?

its not for me

im sure old philidor is rolling in his grave TroyofAndy doesnt approve

to answer your question, its almost strange that 1.e4 e5 2.nf3 nc6 is even popular for beginners to begin with. black has to learn to reply to the italian, the ruy lopez and the scotch , the first has endless traps in the fried liver which is simply so annoying to overcome at low levels , the ruy lopez if white knows to go for c3-d4 is very hard for beginners to understand and are likely to just let white get full center without question, and scotch? beginners simply fare badly when they lack space like in the scotch. This is while ignoring tricky stuff like the ponziani which black will certainly not know how to neutralize. Why would beginners ever WANT to play 2.nc6 ?
and the petroff is simply not a very intuitive weapon at the low levels, black sometimes moves his d pawn twice mysteriously, he has to keep in mind queen tricks etc. Besides you shoudnt be playing with draw weapons at such low levels.
Which leaves you with the only good choice: philidor. philidor is such a breath of fresh air agaisnt all the crazy central tension of the king pawn games. You dont have to worry about fried livers, nxe4 and d4 pin tricks, or the silly fear of your knight getting pinned (Since you will play be7 anyways). ITs such a cozy shell of stability compared to all the opening chaos you dont understand.

Now should beginners play the philidor? meh, hard to say, on the one hand, no one below a thousand will understand with any real depth the subtleties of the hanham structure but the exchange variation puts your pieces in decent squares and is easy to learn. IT does block the king bishop, but then again, people recommend the queen's gambit declined to beginners agaisnt d4 all the time despite it blocking the queen bishop so its hypocritical to scorn it for just that. I think it also teaches beginners the importance of playing soundly but patiently as black, at their level the opponents are minefields of mistake, having lower level players learn the importance of letting opponents do mistakes for them is very important.

The philidor doesn't usually give me problems either. We just trade down to a tiny advantage for white.

at 750 elo I don't think white will be playing a fried liver. And if you're worried about the player ceding the center in the Ruy Lopez - the same will happen to them with the philidor, but more often... With the e4/e5 Nf3 Nc6 positions you learn alot of different pawn structures... you also learn how important development is, and you get to focus on tactics primarily. It's a good way to learn, and isn't theoretical until you reach some at least mid-level elo. But once people start knowing theory I wouldn't play those lines, they're just too played out.

you serious? when i was a scholastic player, the top local chess middle school club in the circuit was composed of a bunch of cuban kids who almost all played fried livers religiously, the toughest among them were about 1000-1200. luckily since i never played 1.e5 but 1.b6 i avoided this nonsense altogether but they were very effective and other than me and a friend of mine from my own school, those kids swept those tourneys.
that was back then, in the early 2000's, now everyone has FAR more access to basic chess knowledge in the openings. Now lower ranks are filled with london systems, baby KID's and people trying to play 1.d4 c4 trying to premature imitate strong players etc. Of course, you still see a lot of 1.e4 e5 but it iis not the almost orthodox baptism of scholastic chess it used to be.
I will bet good money if you are still at a level where you still on your 1.e4 e5 training wheels, scalping through fried liver is still quite common.
idk how exactly philidor cedes the center in the same way in your eyes. The main idea d4 liquidates the center after exd4 not, hand it over, should white try to go c3-d4, natural play with nf6 immediately forces white to play something relatively ackward to protect e4. and if white is not playing the trickiest configurations which at sub 1000 level they certainly wont , a move like nc6 or even the (at that level) weird looking nd7 preserves blacks influence in the center. 
compare that for example with ruy lopez. The most natural way to play ruy as black for a beginner is early bc5, (berlin is not played AS a berlin at that level, no mysterious nd6 here, ) but will a player at that level really know how to neutralize c3-d4 effectively the way black must play in the classical? i bet no. Would he understand why in so many ruys , black plays be7 even when he can play the much more central bc5?

Here is another issue, at sub 1000 levels, it is no great exaggeration that many such players in the ruy 1. reasonably prefer knights over bishops since noobs fall much more easily to knight forks and 2. either do not fully understand why doubled pawns could be bad, or learn super early to overly fear them and avoid them like the plague. so Right away black must be willing to enter what psychologically seems to be ugly terrain by move 4 in the exchange variation. Noobs simply do not understand the abstract ideas of bishop pair activity to compensate a lost endgame, or even why such a move that seems to never be played in king pawn games, (The normally awful f6) is good in the black side of the exchange or why if white goes for an early d4, ceding the center with exd4 may be a good idea.

I remember coaching my best friend's boyfriend briefly on how to play the openings when he was sub 1000 level and what i suggested to him was 1. london 2. caro kahn 3. some slavish configuration. He always got playable positions without a headache and easy to understand ideas. I do not agree with this ancient outdated idea players ought to play 1.e5 as black . Im not one to discourage a bold beginer ( who wants an arduous path i played 1.b6 mostly from 800 on) But i never seen any reason to think the old orthodoxy is anything more than repeated myth. IF i were to recommend 1.e4 e5 at that level i would recommend philidor until they started approaching 900 level. Skip opening headaches and learn pattern recognition and logical ideas till then, most of king pawn game theory is a much bigger headache for black then white. The only saving grace is when the opponent is just as clueless as them and they enter a 4 knights game.

okay what?

Back before chess resources were ubiquitous, everyone played the fried liver at 750. Everyone played it so often that we would call almost everything fried liver if we saw the kings knight run remotely close to black's side of the board.

Although now beginners have more to choose from, like the london or the kid, people are still playing e4 and people are still falling for the fried liver. It's like the scholar's mate.

If you're so concerned about a fried liver for a 750 player (I wouldn't be) just advise the player to avoid the two knights variation. If white can remember to play a fried liver, black can remember to avoid it.

no one said the average middle school scholastic player was smart XD

middle school? I was thinking about elementary schoolers, but now that I think about it some more, there isn't much of a difference anyways.

If they remembered how to avoid it they wouldn't be 750.