I think a bit of nationalism is a good thing and that with all children reciting together they understand that it means all Americans, that we are all one group.
I was in favor of the pledge as it was written until 1954 when Eisenhower in a fit of red fever (fear of communism) added "under god".
Its not something that I have any deep connection with (the pledge not America) so I'm not out to change it and I still believe it should be done, with or without the change, It just annoys me the he couldn't leave well enough alone with something that had worked for 100 years.
We did have a class about it, I don't remember what grade but maybe 3rd, about the pledge and what it all meant. Of course in the 50s the "under god" part was being really emphasized.
I think it give teachers a good way to bring the class to order.
Funny Flag story; I forget which grade I was in but it was before 4th. We had a sort of flag ritual every morning where we took in turn to carry the flag to the front of the room and place it in the holder as the pledge was being recited.
My turn came and I had just watched a TV special about the ceremony of the Royal Guard in England. So when I marched the flag up the side of the class in as much as I could best remember how the Royal Guard stepped.
But my teacher thought I was mimicking the Nazi Goose step and had a complete mental meltdown.
We were supposed to do the part several times (days divided number of students) but that was my one and only day.