Sadly, I’m not surprised. Most Catholic schools and Catholic school boards - at least here in Canada - are about as Catholic as a gathering of Freemasons.
But if Satan can quote scripture, he can certainly find ways into Catholic education programs.
I remember when I was in high school, the topic of gay marriage was being debated in Parliament and divided religion classes.
Those debates in classes turned into arguments. Often, the students disagreeing with the teacher would concede defeat to move on, then trash talk the teacher and Catholic teaching afterwards.
By the time I graduated in 2006, gay marriage was legalized but the debate continued. I imagine it still does.
The best thing to do, as always, is to continue praying the rosary.