Patriot Act Power Mad Flight Attendants don't need common sense. They have their own police force on demand at the jetway.
Once the guy was finished in the bathroom, they could have talked to him and determined that there was no threat to the safety of the aircraft, AND GONE ON THEIR WAY
But the over-officious idiots had to return to remove him from the plane...
Especially after considering the totality of the incident- he told them he had to use the bathroom, the said he had to wait, HE DID, for a half an hour...
At that point would they rather he pees on the floor or go to the bathroom?