I just realized that youtube may be saving people's lives. Ever noticed that the majority of comments after youtube videos are from incredibly angry and hateful people? Assuming it's not all adolescents in the throes of raging hormone shift, I'm thinking that perhaps all those people venting their frustration on video pages are then not going out and shooting into crowds somewhere. I'm feeling safer knowing youtube is around. It is just incredible that people can take ANY subject and have it motivate them to spew their anger and hatred.
There actually is a tool to filter out unwanted comments on youtube (and some other sites). There is a firefox and chrome extension called "Comment Snob". The firefox one is out of date but the Chrome one functions. But not that well since it will filter out good comments as well, using rules like "no capitals, doesn't start with a capital, too many misspellings, etc." There is a "no profanity" rule as well. You could just turn off all the rules except no profanity but of course you don't need profanity to be an asshole. An effective asshole filter would be a monumental invention as it would be great to not to have to have that "noise". However, the only real solution is to ignore the comments.