If everyone has a gun, then others are less likely to start trouble.
If everyone has an abortion, we can bring a halt to juvenile delinquency within eighteen years.
But we need people on our planet to continue our species. We could do an even better job at keeping our species alive if those with criminal intentions were constantly faced with the possibility of their victims being armed.
And we could do an even better job at keeping our species alive if those with criminal intentions didn't have guns.