Worst possible case, having one or two innocent people nicked by stray bullets here and there is a small price to pay for not having places like Auschwicz or Belsen Bergen in your country. The odds are about like those of getting hit by lightning.
No amount of firearms could have prevented the Holocaust, unless one had been used to assassinate Hitler. The Nazis were heavily armed with guns and hatred, inspired by Hitler, and the Jewish people were decentralized private citizens. The twelve million innocents never had a chance against Hitler, guns or not.
It's also a very small price to pay for not having about 50% of all home burglaries being "hot" where the burglar breaks into an occupied house, as regularly happens in England. The English burglaries also are often real home invasions where the burglars capture the residents and force them to disclose security codes.
In the U.S. only about 10% of all home burglaries are "hot" and many of those are accidental, in that the burglar doesn't plan to enter an occupied dwelling. It's not because we're an inherently gentler, more law abiding people; it's because American burglars are justifiably afraid of being shot and killed by their intended victims.