In real-life democratic voting, there's generally a pool of at least tens of thousands of other voters, and each one only has ONE vote to cast. The damage that any single person can do if he pointlessly or maliciously places his vote is minimal. Here, the pool of voters at any given time is maybe a few dozen, and if someone really hates your guts, he can have a significant impact on your overall rating. I don't think the comparison is terribly valid. In a democratic system, you also have a right to face your accuser.