Its very black/white and judgemental. Harsh truth hurts.. it is in almost all cases not personal though, I'm convinced about that.

If you'd get into some type of tags like Slashdot it gets pretty advanced and complex.

The total thumbs down could be hidden. Or the whole result private. Or the voters shown. This leads to a more positive feedback system but the end result is the same. Only the perception isn't. The harsh truth is that there is a limited amount of space available on the frontpage.

Maybe a better discussion is what do you mod up and down, and why?

Perhaps the moderation could be more personal. Like, bound to your account, and if you thumb down a post you don't see it anymore. Its hidden. You see another one. Combined with tags could become (optional) advanced learning. Or ignore posts from specific personae.

IMO this is a bigger, general problem. I experience it a lot when reading blogs...