I really disagree with his point about mastodon’s “followers-only” group behaviour. If I add somebody to a private “group” of some sort, I would like for them to have access to the whole group history, not just the group from that point on.
I also don’t see the problem with using user HTTP-Signatures to authenticate requests.
the author has a solid opinion on the direction ActivityPub should take, but it’s not necessarily the right direction.
Access to whole group history is probably a requirement for a project we are building around ActivityPub at work, so I concur