Only one quibble -
Any weapon is useful for self defense depending on the context. Its perfectly plausible for a hammer to be a weapon of self defense, no less so than a cane, a baseball bat, a wrench, a crowbar, a screwdriver, a knife or a gun. All can be used to deter attacks or counterattack. Some are more convenient or effective than others.
I keep a baseball bat in the garage for this reason, but I carry a knife and I have some more effective tools in the house.
Somehow three male teens carrying hammers around saying let’s ‘kill white people’ is not screaming self-defense tools.
Do you rampage through the streets of your town attacking people with your bat?