Plenty of people have been killed by .22lr. Maybe more than any other caliber due to accidents, because people have often treated it with negligence because of how small it is. "How could this little thing kill a grown man? This is what they have little kids to learn how to shoot! It can't be dangerous if they give it to kids!" Not to mention all the negligent discharges from people forgetting the rules of firearms safety and not checking the weapon to see if it's clear, or people who are going through Grampy's stuff after he's passed away and they pick up the Colt Woodsman he kept loaded for the rats and gophers in his garden. Or tragically, kids playing around in Mom and Dad's bedroom and find Dad's plinking rifle. And there have been plenty of people killed with .22s in homicides and self defense.
The thing about .22lr for self defense is this: it isn't an ideal round for self defense, but if it's the only thing you have then it's better than not having a gun at all. These days, 9mm is an excellent choice for home protection and self defense, preferably when you're using good quality hollow point ammunition. The recoil is soft enough that nearly anyone can shoot it comfortably, 9mm pistols tend to have good magazine capacity, and it's effective. But, like I said, if .22lr is your only option for whatever reason, then that's better than pointy sticks and harsh language.
