e621:rules: "Do not indiscriminately downvote posts based on their content. Blacklist the offending subject matter instead."
I'd bet the majority of the downvotes are out of spite that the pages contain censors (and are probably also the people commenting about it), there's also more downvotes on the non-censored posts immediately following the censored posts.
Not sure if there's some other way to report stuff like this, but anyways, if anyone feels like this is something to look into...