“users will be frustated and leave” exactly the same thing can happen to an instance that adds an instance (or wildcard domain) block. I’d be very surprised if no instance has ever rolled back a block.

Users don’t need to worry about instance blocks on ActivityPub, any more than they have to worry about DNS RBLs for email.

if gmail could just randomly decide to stop receiving emails from outlook addresses and there’s nothing any user can do about it

This is the case right now.

There’s good reasons GMail doesn’t do that, but there’s absolutely nothing technical preventing from doing that, and I can’t think of anything that legally prevents them from doing that.

Using another ActivityPub-based interface is a LOT to ask for many users. They want a simple to pronounce name, they can stick in their browser’s universal bar and be on a sign-up page in less than 3 clicks without making any more choices.

😞

There have been some complaints about Mastodon for years; both specific (“quote tweets”) and vague (get rid of shitty, often bigoted replies for profiles with a lot of followers or with a marginalized identity).

Mastodon largely hasn’t implemented them. Maybe Bluesky has. (I don’t have a BS account.)