That seems to be an easily misinterpreted statement.
.45 will most likely bring an attacker down in pain,
a CZ52 is a very rippin' handgun, and the cartridge is not wimpy by any means. (I know the original use for the round was in smg's but that's beside the point.)
.50 Action Express is so very unwimpy that they converted the cartridge to shoot out of an AR15 platform!
Yes, they are all wimpy compared to the 30-06, or .50bmg
but you can't carry those fairly easily concealed. (except the -06 target gun) Although carrying a .50 ae revolver or D-Eagle would be a challenge too.
I totally disagree and you're missing the point. Always choose a rifle (in a rifle caliber) over a handgun if you're in the position to do so. We use pistols for convenience and the trade off is effectiveness. I'd carry a gun chambered in 30-06 if they could fit it into my SIG P220...but it NEVER will fit. So we're stuck with the likes of 9mm, 45 ACP, and 357 Magnum. John Ross' 50 S&W Uberwhompin' 5 shot revolver is neat, but I find it a bit unwieldy. But, concealed carry generally requires a smaller handgun.
Other posters have said, time and again, to use the largest caliber you can control. Perhaps you have severe arthritis in your wrists...and 32 auto is all you can stand. By all means--use it. Unlike all the passive "victims in waiting", at least you're carrying a gun!
There are about five people in this country who can intelligently talk about terminal ballistics and I doubt anyone here is one of them. I'm certainly not. "Tradition" has a strong hold on the gun world. "Big-n-slow" bullets, "small and fast", "JHPs do..." this or that, "full metal jacket ball ammo is terrible because...", "never use reloaded ammo for defense", and so on and on and on.
This is what I've been told and read by those "in the know". The ballistics of most common handgun rounds are terrible compared to rifle round ballistics. One certainly cannot rely upon ".45 will most likely bring an attacker down in pain" -- total BS (Don't even get me started. The point is killing, not maiming). It could take one to the earlobe or six or more through the chest--there are too many factors involved to even provide a partial analysis here. Many people have died from bullets deemed "inadequate" by "experts"--some were even "Dead Right There". Again, there are so many factors involved in every case (with so many interactions) that a complete and meaningful discussion on a forum is not really possible.
With handguns, keep your expectations low, be liberal with your ammo, and ignore all the hype. Focus on skill in shooting, tactics, situational awareness, emergency medicine, and additional fighting skills like explosive movement, knife and empty hand. You should become as physically fit as possible. If all you can do is shoot, you're missing a huge part of self-defense.
With all that, what do I use for defense? For the most part, I place my trust in skill and capacity. The 9 mm cartridge is perfectly adequate for my purposes, especially with a quality jacketed hollow point round (I like Speer Gold Dots and Remington Golden Sabres). I prefer 45 ACP for many other applications due to ease of reloading (as well as "forgiveness" of errors), accuracy, and versatility.
At the same time, though, I'm training my body through Team Ruthless, improving my hand to hand skills, and learning to use the knife. Force on force shows me tactics and I learn something new every time I participate. It's really a life long road of training, but most folks don't treat it as such, which is unfortunate.