I'm saying that a) the fact that it is necessary and b) the fact that bomb threats were called signals that that the racism problem is so bad that not even the school, which does have disciplinary powers, can effectively do much about it. School is a big part of a kid's life but that can easily be overridden by teachings from family.
The fact that school wide action needed to be taken, not even to punish the culprits but to provide minorities a temporary safe space, signals that they cannot contain these incidents and deal with it on the basis of individual incidents. Usually that's because either the are inept or unwilling to do so, or because the problem is too widespread.
Considering the extremely hostile response to the PoC-only playdate, I'd bet my left nutsack that it's a problem far too widespread to handle the usual way.
TL;DR
What I'm saying here is that there's very likely a lot of hate being taught to the white kids in avenues the school cannot deal with. Like, if they were gonna kick people out for racism, they'll end up kicking out half the school.