He never said that they were "completely wrong". Just casting doubt/sharing thoughts. Regardless, freedom of/from religion has only gotten better in the west for the last few hundred years. Please don't let a few crazies in the US determine your perspective on an entire religion.
Throughout history, most people didn't go to school at all, let alone get taught about other religions (other than “if anyone claims to believe this, kill them”).
There are some states passing laws mandating "in god we trust" be placed somewhere prominent in the school. There's an argument to be made that by doing this, the states are mandating that education systems must promote the the idea of the Bible and it's claims being true.
This post is talking about the dominant religion in countries where the dominant religion is far too dominant.
Of course you can study other religions from time to time, because that doesn't disrupt the dominant one. In fact, depending on how closely religion and patriotism are linked in a given place sometimes other religions can be used as a way to dismiss the relevance or importance of life in other countries.