There's definitely a "downvote if you disagree" ethos here. There's not even a pretense of "this contributes to the conversation, even if I disagree" reason for upvoting.

I know this is how it worked in practice on reddit, but at least the rule was that you were supposed to upvote contributions and downvote things that didn't contribute, and at least a few people followed that rule (or maybe only me).

I wouldn't be surprised if that drives some people away - they see a bunch of downvotes on their comments and think people don't want to hear from them (even if there are more upvotes than downvotes).