>I don't know where else to post this question, but why can I not reply to some comments in this thread? For example I can reply to this comment, but I cannot reply to gozur88's comment beneath yours.

There's an increasing delay between when a comment is posted and when you can reply, based on the depth. The idea is to create a "cooldown" period for people who are upset. You would have been able to reply to my comment eventually.