Religion in the classroom?

I had some free time to read today while the 6th graders were away at PE.  I still have my cool symbol book and was reading about crosses.  It reminded me of the book by Timothy Freke "Is Jesus a Pagan God?"

Today's story in my book was about a cross, the symbol of a God.  Apparently, this guy was killed and resurrected.  Sound familiar?  Of course it does!  It's the symbol of the Sumerian sun God, Tammuz- no?  The Roman God Mithras?  what?  not him?  The Greek God Attis!  Oh you silly people- it sure it the symbol of these Gods, all of whom died and were resurrected for the sake of humanity!

This led to me thinking about a story of a baby- A cute little dude born to a virgin mommy.  God told her she was having his baby who would save the world!  That dude's name was Osiris.  His mommy was Ceres.  Yep.
"Maia, mother of Sakia and Yasoda of Chrishna; Celestine, mother of the crucified Zunis; Chimalman, mother of Quexalcote; Semele, mother of the Egyptian Bacchus, and Minerva, mother of the Grecian Bacchus; Prudence, mother of Hercules; Alcmene, mother of Alcides; Shing- Mon, mother of Yu, and Mayence, mother of Hesus, were all as confidently believed to be pure, holy and chaste virgins, while giving birth to these Gods, sons of God, Saviors and sin-atoning Mediators, as was Mary, mother of Jesus, and long before her time." (here)

This whole series of thinking strangely coincided with a student asking me "How can they teach god in the classroom?"  As she handed me her paper about Moses.
Yeah- How?

They (the education establishment) talk about Zeus and Athena by introducing them as mythos or Greek/Roman myths.  The EE  does not speak of them as if they are real and true God?ddesse/s.  Though I know of quite a few people who would.
However, the EE speaks about Moses as if he were a real and true man.  And he spoke to GOD in this story about Moses.  And he parted the red sea miraculously.
I can kind of see about talking about Moses being a real man- if there is documentation about him- maybe even talking about Jesus- if there was documentation about him.  (If you want to claim the Bible as documentation, then I would ask you to write about Hercules as a real man as well- speak of him as a real story rather than a myth- because his documentation would be a religious text as well).
Why does the EE teach the Christian story as fact, and not the others?  I get that Christianity is a cultural thing as well, as American is predominantly Christian - but we also are supposedly culturally sensitive.  The Buddhist kid in my class might not quite get why this God is real in the books and question what this bearded man might have to do with Nirvana.
Just like the EE teaches that trolls aren't real- and as you know, my ancestors would disagree.  Or that magic(K) isn't real- but a heck of a lot of you would disagree.
So, if you believe that there is no religion in the classroom (and have somehow forgotten that we force our kids to pledge to a flag and nation "under God"), then you are quite wrong.  The EE lies. They are lying liars who lie.  I'd like to either understand this, or change it.