I agree. It is frustrating to see people repeat the same behaviors with seemingly no consequences. But the fact of the matter is, if they are difficult to be around they are already experiencing the consequences. And if you notice someone acting inappropriately, it's like DocJohn says, you can always report it.
I feel bad for people who feel like it's a direct attack and personalize it to the point of feeling like they have to leave the site. But there again, I agree with Lightbulb: this stuff occurs elsewhere in life and we need to learn to deal with it in a constructive manner. If someone has made a comment that I find obnoxious, insensitive, or uncalled for, I will either tell them in person or respectfully disagree. I have not yet come across a situation that warranted reporting, but I wouldn't hesitate if I thought it appropriate.