The opposition to this sort of thing defies logic to me. To quote a comment on Metafilter...
Scott, if you wanted to sign up for Metafilter to defend your writing, that would have been fine. If you wanted to sign up for Metafilter and be incognito as just another user, that'd be fine too. Doing both simultaneously isn't; pretending to be a third party and high-fiving yourself by proxy is a pretty sketchy move and a serious violation of general community expectations about identity management around here.
So he's acknowledging the value of being able to present opinions as "just another person" and acknowledging the value of the author being able to post as himself but then he says those two are wrong in combination? Doesn't really make sense.
As for being dishonest I don't see a sock puppet as any more or less dishonest as any other screen name.
And who exactly is hurt? At best a sock puppet makes it look like the author has one supporter more than he actually has. So what? No one's going to be swayed by one supporter. Moreover I think someone like Scott Adams should have the right to defend themselves without people automatically dismissing it as self preservation.
In the end a sock puppet is just a way for a famous author to present his ideas without bringing his fame into the conversation and I don't see what's wrong with that.