Who took the call and the meeting from PRYSM in the first bloody place?
And unless this was the first school where this gang made a presentation (doubtful), then the group has a track record. The objecting parents should investigate what the gay group has done previously (as the school administrators should have for certain). The school administrators act as if they had no reason to expect this, and that can possibly be disproven.
There have been stories like this before.