Don't know the parish in question or the school, don't know the priests, or the parents, no skin in the game.
So they might be right. (Who "might be right"? you ask. Exactly.)
Or they might be jerks. (See above.)
Anyway, admittedly, no skin in the game.
But here's my thinking, (or rather, my rhetorical questioning):
How is having non-Catholics perform liturgical functions at Mass NOT a practice to which a stop should have been put?
And since in a city such as San Francisco it's a safe bet that most kids can't or don't walk to Church by themselves, how is getting a handle on how many of your charges ARE NOT PRACTICING by finding out whether their families attend Mass NOT part of you mission?
And who thinks the zeitgeist of San Francisco is NOT "savagely distorted"?