What's astounding to me is how long Valve and 3rd party servers have been vulnerable to these types of rudimentary attacks. It's certainly not hard for a professional admin to set up a firewall that will automatically block the source IPs when they recognize attacks happening.
Anyway these loser kids that think they're "hackers" like to pub stomp and troll versus. Before any kids think I "deserve" being harassed like this all I did was return their trolling with sarcasm and didn't give them an inch as far as trolling me went. They spray animated gay and trans-gender pornography on the walls and apparently think they deserve any respect at all.
They blatantly do this to people whenever they feel like it obviously; they are as open about it enough to have a group related to these attacks where you just have to "say you're sorry and they'll stop".
The one perpetrating the attacks I suspect is http://steamcommunity.com/id/howiplay/
(Da Corkster STEAM_0:0:24599375) as he somehow got my personal IP address and was showing it in game and trying to threaten me by mentioning my ISP with it.
His friend http://steamcommunity.com/profiles/76561197960427938
(τaco gato STEAM_0:0:81105) and him administrate the group together http://steamcommunity.com/groups/saysorry
Evidently it's easy enough to automate the process by using something like gametracker.com to find what server a player is on currently or using the same mechanism that gametracker uses to scan servers for usernames. Within a few minutes of connecting to a server it'll get attacked, rendering the server unplayable. I know they can basically just look up my current name using my steam ID and then scan public servers; I'm hoping there's something that can be done by somebody.
They've been reported by multiple people, even with their conversation and threats to me screenshotted. I've opened a support ticket but no response and I guess no recourse for this illegal behaviour for whatever reason.