Relax, I doubt anyone with the ability to produce high-quality thinking is so insecure that (s)he'd be scared of getting a few downvotes on a website.
I wouldn't be surprised to hear that the ability to produce high-quality thinking actually correlated with insecurity. People who spend time developing intellectual skills often neglect developing social skills, and a lack of friends/real social contact then makes them feel insecure.
I think you're probably right if we count more stuff as "high-quality thinking" than I was meaning to do. But if we're rather strict about what counts as high-quality, I think I'm right.
(Also I'll emphasize that I wasn't talking about insecurity in general, but being insecure to such an extent that one refrains from posting high-quality stuff to an anonymity-enabling website because of a fear of getting downvoted.)
People who go back and downvote every post or comment a Less Wrong user has ever made, please, stop doing that. It's a clever way to pull information cascades in your direction but it is clearly an abuse of the content filtering system. It's also highly dishonorable. If you truly must use such tactics then downvoting a few of your enemy's top level posts is much less evil; your enemy loses the karma and takes the hint without your severely biasing the public perception of Less Wrong's discourse.
(I just lost over 200 karma in a few minutes and that'll probably continue for awhile. This happens to me every few weeks. Edit: I mean it's been happening every few weeks for a few months for a total of only three or four. Between 400 and 700 karma lost total I think? I don't mean to overstate the problem.)