It does not even require a "Christian" school for pressure & indoctrination.

When I was in 7th grade, my **science** teacher, who was otherwise an excellent, reasonable man and educator, was also a devoted Christian and in charge of the annual Christmas pageant. Our science class was TOLD we were to be the 'chorus' reciting the words of scripture about shepherds and angels and stars in the East...we memorized it for many class periods. I think I could still do 90% of it.
At that time I was still nominally a Methodist, and just shrugged, though I was bored. It didn't even dawn on me to question either the theology or his right to inflict it.

I know that in some schools in various states, similar things are still done.... along with public prayers. Dissenters are usually too intimidated to complain.

Pressure & indoctrination are what they are... even if low-key and disguised as other things.