The problem is downvotes allow for people to affect the environment with very limited effort, so there's selection bias that gives you that view point that bett

The problem is downvotes allow for people to affect the environment with very limited effort, so there's selection bias that gives you that view point that better comments are at the top. Likewise, those comments at the top arguably would already be at the top simply with the upvote mechanism - the "lower quality" comments would be at the bottom anyway, no?