I know many people who feel the same way--including myself. I am less likely to be upset by insults on the internet, especially if the person appears to be stupid, a troll, or treats everyone like that..UNLESS they specifically target me or my friends, THEN I get pissed off more than upset.
I have less confidence in person--online, I can block or ignore most people (unless they're persistent, and then I usually seek revenge my getting them banned or suffer legal consequences (ie get police involved), and it's fine, I might still be a little bothered by someone saying something, but moreso in the way of "Why would they say that about me? What did I do to upset them?" If that makes sense.
So I do see your points--but not everyone feels the same way as we do, and can't just let most things roll...As a gaia user, and someone who lurks in /b/, I see the worst of most of it, even been the "victim" of many trolls.
But, there are kids on the internet--and people seem to forget that kids feelings are still valid, even though they are immature and unable to grasp that "some people are just assholes." (This is primarily where I disagree with you, by the way, just to explain myself.) But especially if you know you're targeting a child, that's fucked up.

Do you understand where I'm coming from? :)
Children will be children, and keeping children away from the internet entirely in today's society, where we are so "wired in" all the time, is a little ridiculous. You know? I think a lot of bullying could be prevented, if parents and family took a more active role in childrens' lives--instead of just letting them be in front of the computer all day.