I think Steve Jobs was a prick too.
I don't know much at all about RMS, but I will agree that Linus is a jerk.
The difference of course is that Linus doesn't head a company that engages in predatory business practices, ships spyware and DRM (malware) in its operating systems, etc.
So I can overlook the fact that Linus occasionally says mean things to people over the internet. I don't think Linus has ever thrown a chair across his office when someone wanted to leave Linux. Can't say the same for Ballmer, who has very real personality issues: http://www.youtube.com/watch?v=xR-P6HPZgMs
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Finally, I know that this comments+karma format encourages extreme pedantry so let me pre-empt you:
The fact that I choose not to use Microsoft products because I don't like Microsoft or Ballmer doesn't mean I am required to abstain from ALL products whose authors have engaged in behaviour I don't like.
More often than not it's a "lesser of $num evils" situation.