I think I’ve settled on the latter. Disagreement is maybe best communicated by the absence of an upvote? And downvotes work best when they signal something that is just off base, and while not reportable, is not appreciated at a broad cultural level.
There is a quote “You can not not communicate” but on the internet you can. If I get no upvotes, I don’t know if no one has seen it or people actively ignored it and it’s a bad advice to feel disagreed on when no upvotes.
I personally feel frustrated when I get downvotes but no comments because I don’t know why I’m downvoted. Some instances here in the lemmyverse (like mine) don’t have downvotes enabled so I don’t even see downvotes.
I think it’s best to engage in a conversation if you disagree in a constructive way and downvote without comment if you feel this is beyond help.