This is a semantic argument on my part, and maybe I've got it wrong, but I would argue that a virus running in a protected kernel mode on a processor is still a virus and not a kernel itself. Maybe the author had to try to simplify the discussion, but the way I read what was written is (roughly):

"Because Linus is stubborn and in over his head when it comes to security, his kernel can take over a nuclear power plant and kill millions of people."

:-/

The password thing is all too believable...

Thanks.

Cheers,
Scott.