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.
In fairness, it's pretty smart, IMHO: one of the big difficulties in getting a social site started is getting a critical mass of people together to sustain conversation. Facebook already has plenty of Instagram users, so giving them all access to Threads seems like a pretty good way to bootstrap Threads.