Which proves what exactly? A recent survey show that most Americans couldn't name the freedoms guaranteed by the First Amendment. Does that change anything about the First Amendment or what it says? No, it doesn't.
All this will do is teach those church goers something about ancient rejected heresies that they might now have known before.
Good question. And since the people and incidents described happened before there was a U.S., before there was a Europe, and before there was even a Christian church, no one here can "prove" anything more than they believe what one group of people wrote or interpreted, and disbelieve the writings and interpretations of others. Phatus Maximus wrote - it's "faith."