I think you're under a complete misunderstanding of geek culture here Bob. Just because you were bullied in high school doesn't mean that all nerds have been subjected to the same kind of punishment. It may be a reason for some, but it's definitely not the root cause. The real reason is probably the fact that some people are just dicks, and given the anonymity of peoples actions on the internet and the resultant ability to avoid consequences, people are going to abuse this.
Yes it's a problem, and I agree with you on that, I just don't agree with your reasoning. I wouldn't say that nerds as a group are particularly good people. They have good people and bad people, just like any other group. Totally agree with your other points though.