The dislike button does have it's flaws, sure. That's because people confuse it with a disagree button. Maybe a better idea is to have a "STFU Troll" button, or equivalent. You can still have a post full of disagreements, but once someone comes in being a complete jerk, they'll get the "STFU Troll" button clicked so many times that the post just disappears into the abyss. Ok yeah, that idea is just as bad, but it's certainly more fulfilling.