The problem is that comments are often only good the first few times you read them. After heavily hacking on some code for a while, you know the comments. I find the ability to fold comments very valuable.
Yes, I admit that in code reviews, staleness of comments is a thing that tender to get pointed out to me. However, I've since developed a procedure (review comments belonging to any hunk of changes) to prevent that.
Then use an editor/IDE that can automatically hide or fold the comments?