On a local note:
The Catholic school board in my city is reviewing the Education Ministry's recommendations for including LGBT students. Bishop Fred Henry is in a state.
But it turns out that the Catholic school system in Alberta is a public creation, and so is an organ of the Ministry of Education of Alberta. Looks like the bishop is out of luck.
So this Bishop, like our religious leaders here, expects the public to blindly fund the discrimination of their denomination. The Bishop apparently doesn't know, or care, that other religious denominations are not as bigoted about LGBT as he is. The infallible righteousness of God's followers at work again.
And he likely wants to equate the schools there to the off-limits internal workings of a church. If non-Catholic students are attending, because that's their only education option, where else do they go? And if as you say Alberta schools were created as a public entity, with the Church merely having been delegated to run the education program, his case would indeed seem weak.
A similar fault of our own US laws in this regard that appears to be exactly what these Senators want to explore. Fine if a religious entity wants to discriminate internally, but do it with your own money, not the taxpayer's dollar. As soon as they claim a religious exemption from the law, they should also get exempted from receiving public funds.
Obama did it with hospitals receiving Medicare and other Federal money, that were ignoring LGBT spousal rights. Our problem in this case is that the 1972 Law enabling the program specifically made a religious exemption, and no Republican Congress will ever change that, nor can a President unilaterally override it, or so I believe.