The gun factor makes it so much easier to wound and kill multiple people with outcomes that are order(s) of magnitude worse that just that alone overshadows any

The gun factor makes it so much easier to wound and kill multiple people with outcomes that are order(s) of magnitude worse that just that alone overshadows any "people kill people" fundaments in the equation. If you're not allowed (or it's made legally risky enough) to shoot lethal projectiles around, near instantly, and to targets who are merely within a line of sight or just close by then your ability to harm and kill multiple people are heavily bounded by your ability to physically chase and catch individuals. It takes time to exert violence so even if you manage to attack one person the others will use the time for fleeing away. You really have to be busy if you try to implement even a fraction of a mass shooting with a knife. Similarly, knives, fists, batons, and axes keep the damage very local. Even if the astrophysicist's neighbour had stabbed some poor soul thirty times in an adjacent apartment the tragedy would have been mostly contained in the crime scene. Bullets fly far and they fly through, expanding the potential crime scene like what just happened there. Guns turn any situation into a whole another level of danger which is the reason most sane countries have regulated gun accessibility, penalised gun usage, and implemented emergency and judicial response to the point where most criminals don't want to use or carry guns because doing so turns minor risks into show-stopping ones. It could be argued that criminals might often be stupid but even criminals aren't that stupid.