I have to wonder if the vast majority of Sith we see are stupidheads, then the ideology itself attracts stupidheads. I described Sith as "special snowflakes" last week, and it's true: essentially the Sith philosophy attracts the grade school dropouts who join gangs. They can't be bothered to learn things the right way, they have the mistaken assumption that they're special and the rules don't apply to them, and they go around brutalizing people. Sith like Palpatine, Plagueis, etc. are as exceptional as, say, college drop outs like Bill Gates: people who actually ARE special and chafe within the strictures they're placed in.