Why is King's Pawn Opening: The Whale Variation considered bad for white?

"Bad for white" is all relative. 

"Bad" will depend on the skill level of the people playing.  The advantage blacks gains form this move order is a nice lead in development, which is a dynamic advantage.  White will eventually catch up in development, and unless black has some idea of what to do, blacks advantage will disappear.

White is giving up the d4 sqaure very early. It looks like you're trying to play for a Botvinnik structure, but Black doesn't have to play like this, for one thing Black can play Bc5 and f5 right away, possibly with Ne7 instead of f6, at this point if you take Black might recapture with a Knight and you're not going to be able to stop them from putting a piece on the d4 square which will "sit there for the whole game" and keep White pretty strangled. I believe Bc5 (possibly Ne7, I don't remember), and f5 is recommended by Emms against this when he suggests it's now up to White to try to figure out how to equalize. 

Sure it's all relative, and yes when I play it against stronger players things get tricky sometimes but still not enough to cause a real threat.

You're totally right about the d4 square, I usually have a knight hanging there which force me sometimes to make a trade with a knight or a biqhop, if not I can always push the d3 pawn once my I finish my development, this is how most of my opponents play, when they play Bc5 I usually go for a3 then b4 if they play d4 than I'll also make a trade with a knight. So yeah the d4 square is the main weakness point but still this opening has a lot of advantages in my opinion.  

A better way for you to reach a Botvinnik structure might be to start with 1. c4 and then 2. Nc3 and wait until you see what Black intends to do with his dark-squared Bishop before you commit yourself to playing e4. You have at least three good moves that you can play after 1. c4 and 2. Nc3 (those are g3, Bg2 and d3) which will still get you closer to a Botvinnik structure, while waiting to see where the Black f8-Bishop goes.

If it goes to c5, then answer with e3. If it goes to g7 or gets blocked in by d6, then you can complete your Botvinnik formation by e4, Nge2, 0-0, etc.

It doesn't take a "threat" to be worse.  Both the d3-pawn and the d4-square are weaknesses in White's camp as early as move 3.

Every opening has certain weaknesses, but that one is gaping.  It's the equivalent to an "unforced" error in tennis.  With Black going second, sometimes having a gaping hole somewhere is inevitable.  For example, the d5-square in the Najdorf, or the e5-square in the French or Stonewall Dutch.  For White, this is completely unnecessary.  White's weakness is usually occupied by a pawn, not a gaping hole in front of one of his own pawns.  An example of a typical weakness for White is the d4-square in the King's Indian Defense, but with White, you aren't going to have a pawn on d3 with a gaping hole on d4, you will instead be forced to advance the d4-pawn to d5, and the d4-square will be weak, but your pawn structure is c4-d5-e4, and so Black can't get to d4 as easily as his pieces can't cover d4 from the front.  For example, a Queen on d8 covers a Knight on d4 is the White pawn is on d3, but with the White pawn on d5, a Queen from d8 will never guard the d4-square that is weak for White.

This may sound a bit advanced, but it's the only way to understand why 1.e4 e5 2.c4 is garbage, and 1.e4 e5 2.Nf3 is sound, not making d4 weaker than it already is voluntarily.

Thanks, your comment is really helpful 

As an example of playing a Botvinnik structure (played by Black instead of by White, in this case) you could check out my game in post #38 on page 2 of this thread:

https://www.chess.com/forum/view/general/gm-larry-evans-method-of-static-analysis

As Black, I reached this sort of position:

The Pawns on e5 / d6 / c5, with the Bishop fianchettoed on g7 and the Knight on e7 (NOT f6!) mark it as a Botvinnik structure.

In fact, reading all of my posts on the first two pages of that thread might be helpful to you.

Only bad openings cause "threats"

The scholar's mate causes a threat.

It's not about the opening, it's about the middlegame you'll get into.

But sure, it's solid enough that there shouldn't be any opening disasters.

I'll definitely check them out, I also found some YouTube videos that I think will help too. 

It's not "bad", but forfeit's first move advantage. the "problem" with this line is that:

1.white commits his pawn structure too early to  stop a specific plan or formation, (control of d5) when its not clear if Black is aiming for a d5 breakthrough. meanwhile, white cannot even put a knight on the d5 square since black can just cover that square with c6

2 black probably can do a d5 breakthrough anyways via c6-d5 thanks to the support of the queen, trading everything in the center favors black since the d3 pawn is backwards.

if you really like to play as white, this way, that's fine,playing with the white pieces lets you get away with a lot of things, but its too committal to be desirable for most.

this is quite an exaggeration, white in many lines can himself break open the position with d4, or calm the tension with be3. It's not as bad as you make it sound

This is the opening that got me from ~1100 to ~1430 in blitz, I play it both in black and white all the time, it's not as bad as you really think. Maybe I am not playing against excellent players yet but it still do the job (slightly better for black) I usually trade my light-squared bishop for a knight since it's my bad bishop here, castle king side (which most of my opponents do as well) then I push f2 to f4 if they don't take I play f5, also when my opponent have his bishop on c5 I usually go for b4 sometimes I play d4. dark-squared bishop is very important for white, for that I often don't trade it.

Nyanut stop trolling. White's position is completely sound though he has given away the opening advantage. He has a strong bind on d5, he still has his dark squared bishop, he has Nf3 to get rid of black's early Nd4.  

White doesn't have any problems to fix. He has problems trying to attack. 

How are you going to come at white?  

I love pfrens honesty, in a world of snowflakes.

Here's what GM Bologan has to say about it:

1 e4 e5 2 c4
This approach is rather slow for the Open Games.
2...Nc6 3 Nc3 Bc5 4 g3
Even more popular is 4 Nf3 d6 5 h3 f5 6 d3 f4!? 7 Be2 a5 or 7...Nf6.
4...d6 5 Bg2 f5 6 d3 Nf6
Black has achieved the optimal set-up: the 'bad' bishop is actively placed on c5, and White's center is pressured with the lever on f5.

Like the snowflakes that tell you to inject bleach and Lysol?

i played f5 on move 5 and  won the game in 8 moves

https://www.chess.com/live/game/4911704276