Automatically creating a shadow account for everyone on Instagram?
Even allowing people to follow that account?
Sounds like they really wanted to push Threads out the door in a big way.
The block list should be shared, too, like a reputation chain or collaborative filter. "You and user X have both blocked Users A, B, and C. User X has also blocked D. Would you like to, too?" We can each decide the kind of moderation we want to see.