I don’t do so unless I feel very strongly about something—a comment explaining my disagreement or disapproval is more productive
Sometimes, sometimes not. If I see a comment that’s most likely wrong but sounds belligerent, confused or pedantic (or was posted by someone with a track record of being belligerent, confused or pedantic) then I sometimes predict that posting a reply would just suck me into a futile, time-wasting argument. In those cases I happily downvote without bothering to reply. (Other times I prefer to reply to and downvote very misleading comments.)
Sometimes, sometimes not. If I see a comment that’s most likely wrong but sounds belligerent, confused or pedantic (or was posted by someone with a track record of being belligerent, confused or pedantic) then I sometimes predict that posting a reply would just suck me into a futile, time-wasting argument. In those cases I happily downvote without bothering to reply. (Other times I prefer to reply to and downvote very misleading comments.)