The 2 toxic communities which spoiled games for me were the Counter Strike and the DOTA 2 ones..... the latter especially, i have never come accross such a nasty group of people, who basically told me to stop playing till i "got gud". I guess it comes down to those are competitive multiplayer games and I know as a player of other competitive games it can be a bit of a face palm moment when someone totally new to the game does something to cost the team... however the difference between a good community and a bad one imo, is the good ones try to help, without being condescending or rude.
That's my experience, too. And I kind of understand it - both C:S and the various MOBA games out there require you to be matched up on a team for 30 minutes or more, in games that heavily punish the side for having even a single weak member. If you're the sort of person who takes your videogame scoreboard seriously, discovering that you're basically locked in to the next half hour on a game that you know you're going to lose, and the options are either:
1) quit the team, and face whatever punishment the game hands out for quitting early (sometimes pretty severe), or
2) stay there, have a frustrating time ending in inevitable defeat, then take the punishment to your ranking that defeat brings
then I can imagine they would get upset.
But then, pretty much resigning yourself to being on the receiving end of that upset until you become an expert at the game is the reason I don't play them. I'm rubbish (well, mid-table) at CQC, never made it past the third boss of Dark Souls and so on, but I play them anyway because it's no skin off anyone else's nose that I'm being useless.