Since the site allows upvoting of Comments, why doesn't it allow downvoting as well? It seems only natural.
I understand the whole point that "comments aren't designed to be permanent". That's a great theory, but in practice most comments remain in place forever.
And I understand the whole point that "comments should not be answers, but should be asking for clarification of the question or answer at hand". Again, that's not really what is happening here.
Downvoting of comments would provide symmetry for the upvotes if nothing else. And it would provide an obvious way to publicly disagree with the content or tone of comments when deserved. Flagging doesn't really accomplish that, and just leaves it to the moderators to decide to clean up the mess, or not. Adding more comments about comments could do the same, but it would add a lot of clutter (remember "Our Comment Problem") and wouldn't provide anonymity. And it would provide for a more community-responsive ordering of comment visibility.
All in all it seems to me like a no-brainer feature - all upside with no downside.
So what do you think of such a feature?