Disagreement is maybe best communicated by the absence of an upvote?
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.