The problem is that upvotes serve two conflicting proposes. Upvoting raises visibility, so one use is to say, “this is a post people should see.” In that case, you may not necessarily agree with the content of the post, but rather believe it’s worthy of debate. A good example of this is c/unpopularopinion, where the community rules specifically state to upvote if you agree it’s an unpopular opinion, not whether you agree with the opinion.
The other, conflicting, use is to signal approval or disapproval.
You can’t do both at the same time. It’s a flaw in design Reddit had, which they fixed but monetized. Lemmy did not learn from Reddit’s mistake and instead repeated it.
Two conflicting uses for the same action is terrible UX design.