Some quick notes-
.25 gets much of it's bad rep from the cheap pot metal jam o matics that have been popular for over 100 years, even today you can buy a piece of junk Jimenez or Raven .25 for $80 new at a gun show, with a bore that's probably oversized and causes a lot of lost velocity. Even the old junk .22 revolvers had b/c gaps of like .020 , can't get much velocity out of that.
.22 has killed more people than any other because there are so many millions of various .22's all over the world, from complete junk river gun Suicide Special .22 pocket revolvers to cheap auto pistols and rifles, single shots, etc. Even people who don't like guns often have grand paps old .22 rifle rusting away in the closet. Back in the "day" people didn't care as much about stopping power and you could buy a cheap H&R or Iver Johnson .22 pocket revolver for $3 at the hardware store and it was good enough.
You want to talk about a real loser of a defense cartridge, talk about .32 S&W Short. That's basically a cap gun that fires what passes for a bullet, I had some old S&W .32 short breaktops and I was shooting at a poly plastic spinner target, and bullets were bouncing off of it and hitting the barn behind me. .22 LR's and .25 easily punch through the same target. The .32 Short of old could not have been much hotter, even in the BP loading. I think if someone had a heavy coat on it would stop a .32 Short. A guy tried to kill his wife with one and the bullets bounced off her skull hardly injuring her except for surface wounds.......now that's awkward
Good modern .22 LR that's expensive (read the CCI stuff that comes in the plastic boxes) that costs as much as 9mm is very reliable, and .22 Stinger and Velocitor WILL ruin someone's day. Maybe not a manstopper but no one wants pieces of metal punching into their organs or brain. I have a 4" NAA Mini Master and I believe it's the minimum barrel length to get any advantage out of .22 WMR.
That said I've seen insurgents take hits from 5.56 and run behind buildings, we send our troops into combat armed with varmint rifles......but that's a whole different debate.....and I blame the NATO imposed stabilizing rod that prevents the bullet from tumbling in tissue for that......
Tell that 13 year old kid who killed a burglar by emptying a mag of .22 from a 10/22 into him, that .22 is no good.......now that kid is my kind of American