Thank you @weex for making this discussion thread! I have been in about 10 discussions in the last week or so about this. @zzz@eldritch.cafe just mentioned this issue on the w3c github about reply control thats open since 2018 that has a lot of related discussion about this issue.
post update:
I noticed that an issue has already been opened the Wordpress ActivityPub Plugin repo to support this FEP