Well, there's several ways to disagree with someone. I would certainly say that I am more likely to disagree with something if it's biased, facile, rude, superf

Well, there's several ways to disagree with someone. I would certainly say that I am more likely to disagree with something if it's biased, facile, rude, superficial, lazy, or uninformed. All of these qualities—generally speaking, a lack of rigor or engagement—I think are quite worthy of downvoting. To be honest it's very few comments that I see buried at -4 that I really think deserve to be in the black. Periodic concerns aside, I think the system is in good shape.