Earlier quoted context omitted.
That they're technically optional doesn't prevent peers for bullying over it. Source: I was an Australian citizen while in US schools from 2nd through 12th grade. It can be highly uncomfortable to stand silently (and politely) during the Pledge.
When I was in school, almost no one actually said the pledge. By the time I was in high school almost every just sat and continued doing what they were doing. This was in a conservative suburban school in the south.
For example, a Colorado teacher physically assaulted a student for not saying it: https://kdvr.com/2018/08/31/teacher-accused-of-assaulting-st...
Another teacher just tried the guilt trip approach: https://fox2now.com/2018/11/16/teacher-banned-after-students...