Which leads to my point: you shouldn't be using his reasoning to justify your own actions. You are not a kernel developer replying to people on the kernel mailing list (unless you really are =)).
The fact that people look up to him and admire him does mean his cursing and attitude does have a harmful impact: people see him doing and use that as qualification for their own attitude.
There is also the assumption that professionalism means a lot of negative things. The truth is, it doesn't. Being a professional isn't about office politics (despite what some might want to believe). Professionalism is all about context. To slap a definition to professionalism and assume it applies everywhere equally means you need to accept those defining profanity as abusive everywhere in all context.
Basically, if you are using Linus as a justification to allow you to curse or be rude, you are doing it wrong and missing the point.
p.s. I should also note that I believe that anything that worth doing well takes effort. And while it's easier to skip being polite all together, I find that it's usually worth the effort. In the end, you spend less time dealing with discussions of profanity, and get to discuss the actual point. Context matters of course, which is why it works on the kernel mailing list, but not in many others.