Any other time asking a kid to stand up would be acceptable, and if the kid said no, it would be right to punish them. However, like I said, the pledge of allegiance requires you to stand with your hand over your heart whilst you recite the words. She was asked to stand to take part in the pledge, and she refused, which is her right. She then got in trouble for exercising her right.
Got it. I was confused by your second line in your post.
I tend to agree about standing for the pledge. If she was not being disruptive nor confrontational, the teacher should have allowed her to quietly stay seated.
However, I guarantee you that the kid's motives were more to show the teacher up than being offended by the pledge. If she politely said that she did not feel comfortable with the pledge, she should be been left alone.
I bet it went something like this....
Teacher tells class to stand and recite the pledge. Kid kicks her feet up onher desk and says "Hell no, I ain't got to say no pledge to no flag...and you can't fugin' make me".