There have been several waves of the "live streaming" spam. The last one was wiped less than an hour ago, and already the next wave has begun. Hitting the usernames responsible is a short-term solution. Hitting the threads is a short-term solution.
The mods may be trying to figure out how to apply a VB rule (e.g. purge registrations completed within 3 seconds) to curb future waves. And they have to do it while taking care of their businesses and families.