Well, if it is off-topic, it doesn't belong at the top. But if it's thoughful, it should still be readable, so I sometimes upvote comments that deserve downvotes because I think it's been downvoted too much. It's fine if it lingers at the bottom, but if it's still thoughtful, it deserves to be readable.
Actual abuse, trolling, etc deserves to be downvoted into unreadability.