I feel bad for Linus. On Google+ and, now, at Github, he seems to attract irrelevant and foolish (mostly) and sometimes trollish comments. People seem to get starstruck and blabber whatever is on the tip of their tongue without thinking if Linus will even care to read it.
He probably wouldn't join these social networks if he wanted to avoid trolls. And they are probably nice change from LKMLs trolls :)
...and celebrities probably wouldn't fly on airplanes if they wanted to avoid paparazzi. Banning yourself from using things that your friends and colleagues are using is not a reasonable way to solve the problem that some people do not know how to behave themselves. :(