“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.
Some people hate it, including some independent developers. I wouldn’t mind going without it, if there was a Free Software library management alternative. I want something to track what I have installed (because I’ve “lost” things and reinstalled them before) and something that has a decent uninstall.
I also get some benefit from the store integration, but I can understand developers being annoyed at the 30% “steam tax”. I’d gladly purchase using some other method, if I didn’t have to sacrifice library functions from previous paragraph.