Not to be BM but why are there so many bad players in Diamond?

Like seriously, all I get are these diamond 5 players with like 800+ games played who can't even reach 100 CS by 15 minutes, and when you try to help them play better they get all pissy, I bet half the kids in D5 are boosted, Rito please do something about it, make it easier to de-rank or something, I remember in Season 3 you had to be mechanically skilled to be Diamond, now its if you have a 51% win rate with an insane amount of games played.. No BM, just annoying when you're trying to win promos or a game in general and the 0 and 14 top laner with 1300 games throws the whole game..