I don't like contrarians, but I think honest and fundamental dissent is vital.

A recent development in applied psychology is that small incentives can have large consequences. I think the upvote/downvote ratio is underestimated in importance. The ratio currently is obviously greater than 1; I don't know how much greater. (Who does?) This creates an asymmetry in which below zero, each downvote has disproportionate stigmatizing power, creating an atmosphere of apprehension among dissenters. The complexion of postings might change if downvoting and upvoting rights were issued so that the numbers tended to be equal. A downvote should simply mean the opposite of an upvote; it shouldn't be the rare failing mark. Then, the outcome is truly more like a vote than a blackballing.