Sources of karma don't bother me. It just seems like the standards for voting in that thread - both comments and replies - is really different than the rest of the site. Not looser, but different.
It seems like I'm always surprised but the vote totals there - both upvotes and downvotes, when I think I have a feel for what folks like in the rest of the site.
If it's worth saying, but not worth its own post, even in Discussion, it goes here.