Considering the root cause of mass shootings is fascist indoctrination that turns the hopelessness of capitalist alienation into self-actualization through random violence and so mass shootings are actively caused by fascist propagandists like Kirk that Newsom liked to pall around with, he also doesn't want to do that. He wants guns to be slightly more expensive or not as spooky looking, which obviously does not impact the lethality of the comfortable middle class failsons crashing out and wanting to take others with them so they can pretend to be big strong warriors as they die.