why are lower rated players harder to beat?

In my opinion Lower rated players are hard to beat because you underestimate them. Yes they play awful openings. But if you move without focusing and you hang a Queen they will grab it. Keep focus against them and take a break if tired.

Also you were 1400 once. That's pretty good. Don't be sad, It occurs to all of us. I went all the way down to 900 once. But I kept playing and got right back

I'm guilty of this too but I've been working on it.  I think one of the keys is if your thrown out of book quick, assume they are playing a trap opening and calculate.  If they are out of book on move 2 or 3 it's theoretically bad.  So just calculate and defend until it fizzles out, and then mop up.

Also don't let them wreck your position.  For example i used to get a lot of 1. e4 nf6 and I would follow with e5 and chase the knight all over until I either trapped it or they got away. At best I would be up 2 pawns with holes all over at worst I would be even with busted pawn structure.

It's best to just develop, maybe fienchetto your bishops and wait for them to hang pieces.

Even though that is exhausting that is a part of learning. If you are on a bad streak you may end up in a dark place where people play that crap. Put in some effort to refute these and you will be right back. And then you will get back to a place where people play actual stuff.

Alternatively you can avoid playing lower rated players for the most part. Participate in tournaments and go back to a higher rating range. Alternatively, you can do what I've done by using bullet as my tool. I play people, they play certain ways which I consider wrong and I block them and then I don't have to face them again within the pool.

You can also join a club and play their tournaments... Easier to find people who want to get better, for the most part. I don't mind losing to people below my rating at all, as long as they don't play for traps or play with displicence. If they insist on going for that kind of play, I lose all interest in them (and may block them).

You have to make your lower rated opponents beaten without playing blunders.

Yeah, well, but you learn nothing from that. It's not educational, it's not nice to look at. It's just a worthless game. For my own example, look at this (granted, it's bullet and I just play bullet for the sake of dragging pieces around for a minute, not for a high quality game).

Nothing to be gained from that game. No fun had. Just about 90 seconds of nothing of value. Except for making me notice that that player is just playing to be annoying by being a pawn pushing machine. Hence, I said "Can't you play normally?" No response, so blocked he was. And now, I will not have to deal with that stupidity in other time controls. No more facing that kind of disgusting play...

And for any of those who think I blocked the guy because I lost to that play, the second I saw he pushed pawns like crazy I decided to block him. I can't care about any result. Just not playing that kind of stupid opponent.

I admit to being an idiot I'm also offering the OP a way to stop playing in, arguably, one of the worst rating ranges ever for those time controls in this site. When people want to go for Scholar's mate, stuff gets old... When they play the Englund's gambit, it gets old. When they play the Scandinavian main line the typical way, it gets old. When they play the Danish, it gets old. When they play the Italian hoping for the Fried Liver, it gets old. In short, many ways of playing are annoying and get old.

The wrong end of it? I don't find anything to learn from playing for traps or playing in annoying fashion to win a couple of games.

Not really. I am willing to play against anything, just on my terms. Give me a player that will play annoyingly in an OTB classical or long rapid game just for the sake of it, and I won't mind. But they won't play that way for the most part and the OP is quite right about lower rated players being harder to beat because you have to pay extra attention when it's not really warranted.

Here's the Scholars mate guide. You play Knight c6 defending the pawn. Then play g6. After Queen f3 play Knight f6. If Queen b3 trying to attack f7 again than Knight d4. Not too hard?

Haven't seen much of the posts but just from the title my honest opinion is that players that have a significantly lower rating than you get overlooked and judged simply based on a number to classify how good they are (their rating). Now ofc this isn't true for a lot of people who simply play good consistently, no matter who they play, but itz true that you run in to random moves that don't make sense against these typs of players. Usually you prepare for certain moves that your opponent plays in the Opening, but with most players under 1000, you constantly run into moves that throw you off completely. But just play passively in the Opening, and make every move with a purpose and you should be fine.

I disagree with you, on multiple levels, but I think I recognize your frustration.
"the lower rated players are constantly trying to cheese". Chess is about exploiting your opponents mistakes, so let them make the mistakes and punish them
"nobody plays good respectable openings". It sounds like want to focus on theory rather than gameplay. You want to be a very good chess player on the condition your opponent plays the moves you expect and have prepared for. I am happy that chess at our level isn't reduced to a small set of viable openings, like it is at GM level. We still get to really play chess.

But I have to admit, I do experience cheesing when I play blitz. I am confronted with a lot more unfamiliar positions, caused by more random moves or tricks. My blitz rating is significantly behind my rapid and even daily rating. It just never occurred to me to blame the low rated players. I just assumed I needed to improve my skill.
Of course, it frustrates me when I can't beat lower rated players in blitz, even though I believe I should be able to. And if I review my games, I know I can beat them.
In contrast, I find playing the higher rated opponents much more frustrating. Playing a game with no blunders and no mistakes, just a few inaccuracies and still being behind all the time.

Basically, if lower rated players are the problem, you should be able to overcome that challenge. Beating the higher rated players, that is the real challenge

you sound hurt

I'll give you the quick and dirty: 

The reason they seem hard to beat is they don't play... right. They don't play the best moves, but they do often have logic behind their ideas. Oftentimes, you may underestimate them, and then all of a sudden they're winning. You shouldn't expect theoretical perfection in openings. I'd study the first ten moves of each of my openings, then the first ten moves of all sidelines. Just play logically, and you should beat those who play illogically. If they really are bad, they leave you chances throughout the game.