If school shootings where 3-10 die are enough reason to pass gun control, then surely a human stampede where 150 die is a good reason to pass mandatory social distancing.

It doesn't work like that. School shootings are propaganda inflection points for left wing gun control, but liberals don't care about school shootings. They want a disarmed populace so the populace can't rebel against socialist policies that are unpopular. Left wingers always lust for a State monopoly on violence.