I see the down voting more often as a method of saying “this is a troll” or “this opinion is unpopular because it is evil/ makes no sense”. I’ve seen plenty of unpopular opinions that have decent ratios while genuinely being unpopular.

I think it’s similar to how the right wing views the first amendment in the US. You can say whatever you want that’s unpopular. Noone is stopping you. But that doesn’t mean that you’re entitled to upvotes for being a bigot or troll just because it technically fits the subject of the sub.

Similarly, I’ve read people encouraging voting as a way to say that the post benefits the conversation. Down vote trolls, posts without adequate backing of ideas or actual dangerous comments and upvote posts that contribute, even if you disagree, then disagree as a reply.

For example, in a post, “a hotdog is a sandwich”, upvote a comment that says, “meat & bread = sandwich” then reply, “you are an idiot” (then expect a downvote because your comment doesn’t contribute.