Why not allow us to choose what puzzle rating range we get in rated puzzles?

Why not? Pretty much every other site does it.

good question

I support this motion

People could spam a ton of 2700-3500 mate in one/mate in two puzzles... allowing us to choose themes for rated puzzles shouldn't be done. Lichess does that yes but I prefer the chess.com system anyways...

Bruh not themes..... Only the ratings. Like I could choose +600 or -600 etc.

Unless it was made so that puzzles with a lot lower rating don't change rating on pass, then it could be gamed to boost ratings.

Isn't that how it already is though? You get more points for completing harder puzzles, and lose more points for failing easier puzzles, etc. Puzzles are largely non-competitive anyway, and solutions can be looked up in advance using an analysis board presumably, so if people want to game the system then they can already. Doesn't matter to me what anyone else's rating is, but the lack of versatility as OP said is frustrating.

Currently it seems the presented puzzle range average is stuck hundreds of points below one's current rating (e.g., if your puzzle rating is 2000, the typical puzzle range offered is 1400-2000). To get hard relatively hard puzzles (>2000) you have to get like at least half a dozen of these correct in a row as some kind of qualification. If you're averaging 60% correct, it's pretty difficult to get any puzzles during a session that are above your rating because of this (rarely one is thrown in at random). So yes you can get harder puzzles by increasing your rating over the long haul, but it's much harder to get to relatively hard puzzles in the short term.

There does appear to be a selection bias in the algorithm to puzzles lower than your current rating, at least currently. I know in that algorithm has changed a few times in the past, though I don't know specifics. 

Yes, there is a HUGE bias. 90% of my puzzles are rated lower than I was when I solved them.

Exactly. I do agree with @Martin_Stahl though because people are gonna farm lower rated puzzles. I think they should make it so that you can't gain points for puzzles that are more than 700 points lower than your rating.

For example, if the lower rated puzzle has a point pool of +5 if you get it right and -16 if you get it wrong, it will be really easy to farm. If you get 80% of the puzzles correct (you could probably get more), you get +4 points. You could solve the puzzles quickly since they are easy. Free points.