As this new field been discussed by #ActivityPub contributors? Has the spec well written and reviewed? Has all security aspects been considered? I don't think so... It appears that this field is wrongly designed: if an #ActivityPub server doesn't understand that (currently) proprietary field, it would allows comments. Useless, and kind of confusing for the initial user...
@malendur It's meant to improve usability -- that's it.
Today if an authoring platform doesn't allow comments on a post, there's no way to communicate it. Since 3 platforms support this function, we've gone ahead with the solution we have today.