I don't think they "bought into" anything except school safety.
You're entitled to "think" what you want.
You asked where the racist term entered the equation - the school sided with the Mexicans and brought it in.
I will take them at their word.
The school is no more safe without the flags than with them. By not choosing a side, the school actually left it open to the students to fight it out. The school should have chosen a side and ended the debate.