Why can't we comment on [dead] posts?

Did this behavior change recently? I recall being able to reply to existing comments on [dead] posts recently, but now that capability seems to have been removed.

These actions seem anti-user. If the post is already dead, no new comments can be made on the post, which is bad enough, but could be justified for moderation purposes. However, why can’t we reply to [live] comments, simply because the post they are attached to is [dead]? It’s bad enough that old [live] posts get locked, basically freezing them in carbonite, a state indistinguishable from death only in that it wasn’t triggered by user behavior.

A related issue is that downvoted replies with upvoted children may be collapsed or [dead] even if the downthread discussion is of higher quality than other top level comments.

Maybe make it so that user flags have to select a checkbox/radio button reason for the flag or fill in a text box? Would probably not help the issue in title, but slashdot’s vote reasons and meta-moderation system captured a lot of user interaction intent that few platforms have revisited. Emoji reactions would maybe be the closest thing I’ve seen lately.

Thoughts, suggestions for more thoughtful interactions on HN?