handguns are really a defensive weapon-the body count in this story is s in that he had that much time with that many defenseless targets that chose passivity over mounting a charge that would have overwhelmed someone that size 100% of the time. small guy, many people within 10 yards, low rate of fire of light and slow rounds, he might get off five hurried shots before people are on top of him rendering the gun useless.

when you choose a handgun as your offensive weapon in an area with lots of people the police generally show up or someone else has a gun.

the second there's another gun in the mix, you're no longer on offense. if it's some guy with a CCW pulling out his USP in a big crowd, you're being hunted unless you can watch every hand in a building. then it's a gunfight.

the second the police arrive you lose because unless you're shooting ammo not sold to the public out of a fabrique national(and that's still a reach) you're shooting bullets about half the velocity needed to reliably defeat the body armor the regular cops wear. they show up, your time on the offensive officially ends because a handgun is next to useless at keeping distance between people moving towards you with any kind of coordination because when someone's moving two of their friends are shooting at you.

you go beserk with a handgun you're going to invariably die and you've gotta find the perfect wave of a murdering-spree like cho did to have any chance of killing that many people.