I just want to tag on with my personal experience that happened a few days ago.
I was in an NA HL lobby, it was on Viaduct. I played Medic and was rolling kritz. I pushed up to mid with my team (via comms) and kritzed the demo, who was in mumble along with everyone else, but wasn't talking. Instead of spamming out the enemy combo that was holding behind rock along with all of the rest of their teammates (blatantly stupid), the demo focused on the engie that was wrenching (and missing every shot, mind) close up. The entire kritz was wasted because the demo spammed at his feet and tried to kill the engie, missing every time. Of course, I called out the demo for it in mumble, but I wasn't overly aggressive. Everyone else saw and started name calling and other immature shit.
By the time we respawned (the demo ended up getting the engie at the very end of the kritz, but blew himself up with the same sticky), obviously we were needed by our team. The demo was trying to type in chat and apologize rather that hop on mic. Obviously he was a little frustrated. We lost the first round, so then round 2 begins.
Straight out of the gate, everyone attacks the demo in mumble and forces him to switch to heavy so a more experienced player can hop to demo. Fine by me, okay. But now the heavy stands outside spawn typing to us and trying to attack back, or defend himself, or whatever, rather than sucking it up and going back to playing the game. He also called us out for tryharding in a lobby, apparently. I guess not wanting to lose is tryharding. Anyway, eventually the team kicks the heavy off to engie by the end of the game, and we get a new heavy. Near the very end of the game, we hear crying on comms but we can't figure out who it is.
After the game, Center dumps everyone from the game into the same mumble channel and we say our GGs... But then the demo/heavy/engie starts speaking up. She had been crying on comms during the tail end and I really felt bad, so I apologized and left, not wanting to deal with the possible shitstorm.
Apparently the rest of the players all ganged up on her (even the one other girl in the match) and bullied her for playing poorly (demo is apparently her worst class and she was lobbying to get better), being a sore loser (wat), etc. It really took a toll on her. She added me to friends later that evening (like, 6 hours later; I was in the middle of a cast at the time) and we talked a lot about what happened. Apparently talking it out with her (supporting her, etc; I of course apologized because I'm not a dick) made her feel a lot better afterward, so that was nice.
It absolutely sickens me how hostile and immature the Center community is. I'm not really sure what's causing it to get so bad, but it's leading me to drift from doing lobbies to doing pugs and scrims. It's gotten worse than pubs. Sure, the OP's rant seems like a day gone bad and things are being exaggerated and whatnot, but I know what I saw and Center is beginning to sicken me.