@jdp23 1. They don't need to start an ActivityPub server to do this, and it still is disproportionate effort for a small, niche user base.
2. They have no means of actually doing this for users not on their service. Also, inasmuch as they can, point 1 still applies.
The last point is simply a reiteration of "Meta are evil and so they will do evil things even if they make no business sense." Because it doesn't make any business sense at all.