Those "protections" are in place for the protection of the government, not the citizens. That's also why the US tried to classify encryption as arms and why they passed the gun control act (people nowadays might think modern gun control was passed to help school kids, no lmao, it was passed in response to the killing of JFK).
I don’t think anyone thinks gun control was passed to help school kids. People have been begging the govt to pass stricter gun control laws to protect kids for decades with very little success.
I don't have the citations to back this up anymore than you did, but it was also passed because of the rise in Black Power movements walking around with guns.
I used to be an obnoxious gun control advocate until I learned that California's gun control legislation was brought about in response to the Black Panther's patrolling predominantly black neighborhoods while armed to protect the people of the neighborhood from state sponsored (police) violence.
Reference to start from: https://www.kcra.com/article/liberty-limits-black-panther-pa...
This topic is full of subtlty so recommend reading the sources from that article and so on.