There could still be a problem if comment threads were sprinkled with huge contiguous swathes of hidden comments but does that actually happen?
It doesn't happen often, and so doesn't seem to be a particularly serious problem, but when it does it's really bad and the growth of such subthreads is very hard to stop.
I find the fact that even obviously aggressive and stupid stuff tends to be replied to in a polite and informative manner one of impressive things about LessWrong.
See the hidden comments to this post for an example. Just one user causes the damage directly, but that wouldn't happen to the extent it did without the polite and informative replies of others that fuel the conversation. Good contributions to bad conversations have negative net consequences.
What are these negative net consequences? I enjoyed reading the good replies to that conversation. If you think the problem is the volume of conversation, then you have to explain why shutting down long "bad" conversations is worth losing shorter elegant responses to bad points.
Lesswrong puts a lot of stock in trying to fight human biases, which seems to me that saying "Don't do that!" with negative karma, and then rewarding people explaining why not, is exactly what we should be doing.
Has anyone yet mentioned or reported that for the last couple days, the "karma for last 30 days" is showing zero for everyone? And that we no longer can see the top contributors for the last 30 days either?
Do we have an explanation or estimation for a bugfix on this?