This is a guess, but I think it's as much likely that they're just a little out of the loop about that. The guy down there mentions that they were stopped the last time they tried to come, so it'd be hard to pick up on the fact that she isn't possessed anymore, if it's taken them a while to pop back up.

Or they know she isn't, and just feel that she's a good substitute if they can't find the actual "culprit". Either way, it's annoying to me.