It doesn’t matter if the most upvoted comment is pro or against subject in discussion. All that matters is bolstering a comment that is minimally compatible with participant’s thinking and making it win against the opposite argument (competing and most voted one).
So it seems that the most satisfactory comment (for most readers) doesn’t really matter at all. What matters, before anything else, is visibility of an opinion that somewhat aligns with one’s thinking, rather than writing or finding the most corresponding comment for that subject, fully compatible with reader’s perception.
I think a good rule of thumb would be to only upvote a comment if you think it’s not only good, but that it should be higher in the thread than it currently is. Then the comments already at the top wouldn’t end up so overweighted.