I think the "I would say" statement would have been better phrased as "I'm as likely to say..."; I get the feeling that was the speaker's meaning. There is also a distinction to be made between being racist and white supremacist; the Asian student in question is denying white supremacy. He's not saying he isn't racist (and I'm not saying he is). Those things are similar, but are not the same.
The school sounds like it obviously has had some problems with racism, and like other public schools in CA probably has a dress code that is meant to curb display of gang affiliation.
I also don't doubt that this was the work of some smart@ss kid who used the privilege of being 'first voice' to create something out of nothing; all it took is one idiot to claim a reality that the school was then obligated to respond to.
But as usual, great post!