No, this is the truth.
In fact, just a few months back I had to teach some of the posters here on CF what the Athanasean Creed was; even though it was considered a pivotal and foundational Creed once upon a time, a number of folks here had never even heard of it.
Or there have been numerous cases in which a "Good Christian" decided to debate the Bible with me, only to admit that they hadn't actually read the Bible cover-to-cover yet and so were unfamiliar with the very book that they were trying to defend. This is on top of countless incidents in which I had to explain to people the process behind the formation of the Biblical canon. (Mainline Christian ignorance of how the Bible was assembled is so great that when I took non-denominational Bible survey classes at a local college the professor spent the first two weeks just going over this process so that people understood it.)
So yes, it has indeed happened to where we've had to teach Christian history to Christians.
I think we can all agree that within every religion on earth there are those who are not up to date on every point within their religion's history. No matter who they are, whether Mormon or Christian, Jew or Muslim, Hindu or Buddhist, etc, etc. Of course, those new to their faith would still be learning such things. Should we think lesser of them for that earnest fact? And, sadly, we all know there are those lazy 'religionist' of every single stripe, who even faithfully attend 3-hour services, and, yes, do the same of their respective Sunday schools! But when pinned down, cannot answer even the most rudimentary of questions within their faith? To remain honest before the Lord, we all must admit to knowing such people exist in every church. Should we discount their lack of knowledge? No. They are there, when so very many don't bother in this world. It's something! Pray the Lord to make them thirsty for His truth, is all we all can do. True? We cannot admonish someone into the Lord's presence, or demean them into loving their neighbor more. Doesn't work. If done so, they will only offer lip service, and soon learn to avoid their admonisher.
As far as religion classes in colleges go, not all that attend such classes are Christian. It would be foolhardy that anything more should be implied. Especially if the college is not a Christian college, but a local community college with non-Christian professors teaching "religion" classes to a diverse group from bible-believing Christians to non-Christians, to those looking for extra credits alone, as is so often the case nowadays. Even the rare earnest Christian Professor must contend with students who have no real interest in the subject but to use it to graduate. Not all Mormon students in BYU know their own church's history, not all Protestants in Oral Roberts U. know theirs, not all Catholics attending St. Mary's knows their very long history either. (When such a rich religious history stretches back to Jesus teaching simple men next to a lake about loving their neighbors? Imagine being Jewish, how many thousands of years of history and culture there is to learn, especially if EVERYTHING was determined as 'critical' to their faith!) Thank the Lord that Jesus said the only thing critical to the Christian's faith is--Him and love! So simple a child can know it.
How sad a world we live in, when God becomes nothing more than a vehicle for education, elevated above love or genuine human kindness for one another. Not all are willing to learn how to love one another--and it is a learning process. Isn't it? (Maybe why the Lord so humbly referred to it as "'practice' these things I have shown you?") Mormons have learned of their own history from Christians. Christians have learned of their history from Jews. Muslims have learned of their own history from Jews. Jews have learned... we all get the picture. Learning goes on, as it should. But the Lord remains above our puny attempts at "knowledge", thankfully. So I think we can all agree, again, that it's a lifelong learning process when it comes to God and His Word! And what a joy that is! Where one can never crow (with any actual humility) that they know it all, preening, "Ah HA! I have more religious knowledge than you do!"
"Oh, really?"... replies our All-Knowing Lord. "And what was that My son, Paul, once referred to as consisting of nothing more than 'clanging symbols and noisy gongs?'" From which famous chapter is that from?"
Yes, Lord. Learning to love can never end. Spot on. As always.
Now if someone would kindly tell me what the "Kawaii, tutu, and Ebil" emoticons mean, I would appreciate it. Thank you and God bless.