Many of those people now have more than 500 karma, by appealing to the majority opinion, so they're allowed to downvote all they want, skewing the demographics of the site. If you've been here a while, you probably noticed the shift in discourse and submission quality.
It happens with all "Nerd News" sites; they're great at the begining, then the people that shouldn't be here start coming, and the signal-to-noise ratio gets closer to 1:1.