My favorite toxic community is Dota 2. It's almost comical how quickly dota players will go into full rage
I have a story from original DotA with the WC3 engine, from roughly 12-13 years ago I think. This will probably be interesting only to people who also played it, here goes.
I was around 15 and I was playing Ragnarok Online (MMORPG) and our guild was in position where we had to ally with another guild to actually succeed in the War of Emperium (a full-on server war between guilds for ownership of castles/keeps), and by succeed I mean really matter in it because otherwise we were fairly insignificant, and looking back on it, pretty much every other guilds were full of douchebags.
But I guess it wasn't obvious to me back then, and so we allied with one of the coalitions and we got on alright, I think I might've been leading our guild back then or at least was important enough as only one capable scholar/professor (a class in that MMO), so after one of the events the douchebag guild members asked me to play DotA with them, they apparently needed one person to make it a full 5v5. I agreed. I never played DotA before.
Most of the players were actually fairly nice, especially the ones who asked me to play, but there was also one guy who apparently played really well but also was raging at every single thing. I obviously fed my lane hard and after like the third or fourth death I ended up back on respawn with enough money to finally buy something. Except I didn't know what to buy for that guy (I think I played Tidehunter). So naturally, I ask in Teamspeak (or whatever was around back then, I don't even remember) what to buy for this character, and the raging guy flippantly tells me with barely concealed anger "just fucking buy five bracers and you'll be fine".
It's been about 13 years and I still remember this shit.