If schools are deemed safe, why not trick or treating?

I feel like I’ve been getting confused a lot lately. Maybe you can help me make sense of something.
Schools are open now. Many classrooms have 30+ children in them; all schools have hundreds of kids in the buildings, all at once.
But Doug Ford has said that the idea of Halloween makes him “nervous.”
Now I’m pretty good at understanding others’ points of view, even if I don’t agree with them. I can usually figure out the logic and at least get why people do the