I use IRC often. You have to remember the Internet is mostly used by Americans and 85% of Americans are white. That pretty much explains the 1/5(guess from your perspective).
Oh that's not the issue, even though I did run into actually quite a few foreigners on Chatroulette, like from chile, and I'm currently talking to this lady from denmark, good lord she's hot. But I met her on chat roullete too, with that said, the odd thing is that I never saw a minority jacking off on there though. That's the thing. It wasn't like I was looking, but definitely at least 1/5 people on chatroullete was jacking off and ALL of them were white. And while I've ran into other minorities, they were never jacking off.
My cousin's friends use that shit. When they would go on there, it was cawk-tyme half the time. It was re-dick-ulous.
The best by far is tinychat, cause they are operated by hosts, whoever decides to create a chatroom and others join, but the best part is that if someone does try to do that crap, the owner of the room can give them the boot immediately, it's pretty cool. There is another chat roullete type service too but I can't remember the name, I was on there for a few hours and I didn't run across anybody doing it, but it could be because it's not as well known.