Pledge of allegiance?

So, I'm an immigrant living in a fairly liberal area in New York State. I recently started working at a local school district as a TA and was surprised that they do the pledge of allegiance every single morning (even though I know it's a thing that happens in America). So far I've done it every single morning, and I know that the other teachers and aides get upset at students for not doing it but like... How serious is it to not do it?

I'll probably keep standing and putting a hand on my heart but probably won't bother to actually say the pledge (until I'm a citizen at least), but is that seen as rude? There's a few students in the class I work with that have behavioral problems, and the teachers act like not doing the pledge is a part of it?? I can't help but think that that's a bit much, especially in a mostly liberal area?