If you fall on the side of, "It's stupid that they're doing that, it's just harmless fun" instead of on the side of, "I guess for the kids who it's not inclusive of, it's nice not to have to deal with, and for the rest of the kids, they probably still have plenty of trick or treating and costume wearing and halloween fun regardless, so, no big deal", that's kind of weird to me.
For the record, I'm pretty unconcerned with the entire thing in general, and don't really care. But reality is that nobody is being oppressed through this decision, and some little kids are probably relieved, while the rest have plenty of alternative means of celebrating and having fun on a meaningless holiday if they want to.
If you like Halloween and you grow up with a certain sort of tradition, I get how people getting rid of it can seem like an overreaction or unnecessary or whatever. But that's because you're starting from your pre-conception. The real question is why does a school need a Halloween parade in the first place? If there's no less or no more need to celebrate the holiday than there is to refrain from it, then just refrain from it in state/federal spaces.
Isn't it interesting that the political party who favors less government interference and control also seems to get a bit bent out of shape when the government stops endorsing their specific holidays?