Why do high level chess players consistently make really strange looking moves?

more often then not black will play e4 and your bishop ends up worse than blacks on g7 and yours is not good. It seems pretty because the bishop has dark squares to move on but its useless here

Nonsense, on both counts.

Black very rarely plays e5-e4 in that sort of position (and if he somehow manages to do so, White can reply with Bd4)., and White's dark-square Bishop is indeed a useful piece.

Is no one going to talk about how black has an immediate win at #13?

Basically, it's a matter of not just making good, solid, principled moves but of increasing the chances of a win. It helps when the best moves look wrong to the opponent. For instance, in that last King's Indian game, Bd2 isn't a completely bad move, although the strongest move in that position, Ne1, has to be better. I usually play that bishop to d2 but after Ne1, so this player was experimenting with move order. It's probably incorrect but not losing for white. It's actually a known variation of the Mar del Plata. I play g4 against that and Be3 in one move doesn't go with it if black gets the moves right, so my bishop usually goes Bc1 - d2 - d1 - f2. It's just a case of white being in the best position to prevent black's kingside attack and launch an attack on the queenside. Bd2 is the most accurate placement but after Ne1. Just trying to help.

Black's g7 bishop is black's worst piece and the one on c8 is black's best minor piece. Black's knights come somewhere in between. As white it's correct to try to swap your f1 bishop for black's c8 bishop. If you manage it, black's chances of winning are reduced to near zero. White plays the opening so that black's g7 bishop is hemmed in by his own pawns. That's why Ne1 is such a strong move for white because, if black can play Nh5, then it can jump in to f4 and if white takes it, the diagonal is opened for black's g7 bishop.
I use normal strategy as white. Open the c file or better still, if black allows it, the b file and get the rooks and queens off fast while creating threats. Also try to swap a knight for black's light square bishop. Then manoeuvre very fast on the Q side. White's light square bishop, at this stage, is far better than black's g7 B and can play a vital role in white's attack. Often white has won a pawn before black gets the g7 bishop into play and has a won game. I also sometimes threaten to win two pawns for a knight, with a winning pawn advance. It's extremely difficult for black to defend against everything if white plays accurately. And that's why white attacks on the queen's side.

Chess players sometimes put knights on the edge of the board to “re-route” them to a better spot where they can see more squares. And sometimes, they prepare the knight to move on an outpost. And when White or Black pushes a flank pawn, rather than a central pawn, I think that they are trying to start a pawn storm on either the queenside or kingside. 
Sometimes, when playing chess, I look at my pieces, and find that my bishop or one of my bishops is not controlling a lot of squares. So I move it backward so that it can gain scope on certain diagonals.

And sometimes I move my knight twice in the opening because either it’s been kicked by a pawn, or it doesn’t see much squares.

Backward moves can sometimes be beneficial, and sometimes, flank pawn moves can start a pawn storm if you’re opponent’s not careful.

That's quite a good O.P.

I played in a lot of otb tournaments and generally speaking, competitors in the range 1750 to 1850 FIDE tend to play in a very solid and predictable way, and maybe that's their weakness.