Nothing, Jim. It's what normal people do all the time when they're embarrassed of their record. You know, have a dozen handles, ready to move to a new one at the drop of a dime once you get exposed as being a terrible person out to help other terrible people do unspeakable things to the most vulnerable out there. That's Gary. That's who he is, who his posts prove him to be, and his actions of changing screen names and deleting threads is all part of that persona.
And now he's spinning out for the past 48 hours, so expect a new handle soon once he completely loses it and posts something incredibly vile again -- or deletes an entire thread once it turns against him as he's wont to do (like the coward he is).