“This section does not prohibit a statement of a sincerely held religious belief or moral conviction of a school employee, school volunteer, pupil, or a pupil and parent or guardian.”
Which still appends a whole other phrase of acceptable behavior.
But, how, precisely would a court differentiate between a sincere and insincere belief or conviction except in the case of corresponding to religion? The KKK can argue they have sincerely held beliefs- it would seem fairly implicit that the definitive defence (an a priori the definitive protection) would be on a religious basis, as this is the easiest to materially approve.
Actually, it's arguable the religious defense would be more difficult to prove than the KKK one. Going to church is no real guarantee of religious orthodoxy either held or actually practiced. (These are very large organizations with very large memberships and ranges of opinion; and many of them have no institutional controls to define and enforce an orthodoxy.) Membership in the KKK carries a lot more weight that your beliefs are where you say they are.
And in either case, such proof in a court of law is difficult or impossible, dependent solely on how much time and effort the prosecution is prepared to throw at you. Even a documented instance of the behavior in question can be introduced as evidence against in most cases on a number of passages operative in most Abhramic religions. (The prophet Micah's "To love justice, hate inequity, and walk humbly with your God" comes to mind, and doubtless I could introduce others.)
I'd argue that all criminal law can be seen as in some form restricting behaviour, though.
I didn't argue this point. You missed mine, which is that by claiming only sincerely held beliefs or morality can be considered legitimate and all other stuff is lies and only truly meant to be hurtful, thereby allowing them to appeal to greater penalties and demonization. (Whereas in reality the majority of bullying is closer to thoughtless than sadistic.)
This is symptomatic of the people who are behind this cause and their behavior.
I'd also argue that, for the Republican party, the religious motivation is the political one, and vice-versa.
Doubtful. This is not a stand on religion as much as it is on feel-good morality, much like the videogame bans peddled by the same sort of state-to-state political shysters. It was passed not with intent of making operative law, but a political statement.