Dang Janq! Despite all the hard work and thought you obviously put into your post I still gotta say regardless. Does a .380 FMJ have enough horse power to get to the vitals and do it's job of stopping a BG. Answer is a simple one... Yes. It has proven itself over and over in ballistic gel. The only real reason why law enforcement doesn't use the rounds is more than likely due to the better options for it officers who are not concerned with concealed carry. If I was a LEO, I too would be carrying the largest caliber and firearm that I could. To compare what Law enforcement carries vs civilian carry options is a stretch IMO. LEO's search out the BGs were as, we as civilians defend against them, not the same thing IMO. I will agree with the statement "carry the largest caliber you can shoot effectively" but in the same breath I'll add, if you can put a .22 into the noggin of some low life I'm sure he'll drop into a heap due to bullet placement, not so much the caliber that was used. Sure bigger is better, but when you get to a certain level the rest is just gravy.
IMO, .380 or possibly .32 should be the lowest caliber one should carry for defensive purposes, but like it's been said over and over; something is better than nothing. For the record. I have been carrying my 650 .357 and my LCR .38+p for the last couple of months but not for fear that my PPK wasn't enough gun. I still carry it from time to time, but I wanted a more reliable firearm, not caliber. My PPK loaded with BuffaloBore 100gr HC flat nose stuff and the round has 295FPE and travels at 1150FPS, the only thing it lacks comparatively to the .38 is bullet weight. The .38's have been putting BG's in the ground for a long time, and IMO, the .380 FMJ especially the truncated FMJs are a very effective defensive round if placed in the BG properly. All the talk about " A BG with a knife can close the distance in this and that" is great, but what it doesn't say is, Not every BG can do that and not every situation is played out 100% to match that.
IN closing I just want to add that I am in no way disagreeing with you and the data that you have posted. What I am saying is this.... I have seen a guy shot by a .380 sitting right next to me in a truck and I can tell you for a fact, the guy was out for the count. He shot himself in the foot by accident and if it wasn't such a serious situation I would have laughed my butt off, but fact is he was down and couldn't function by a wound to the foot with the .380. It was a round nose FMJ and believe me, it had the horse power to go through 4" of his heal, and a pair of military boots and darn near the metal floor of the truck after passing through the carpeting. Oh and the post that said due to the round nose, the wound will close up around the entry; WRONG! I could clearly see a 1/4" size hole in his foot at the hospital while I waited for the Police to arrive. Sure the entry wound wasn't as bad as a HP would've been, but it sure didn't close up either. My point is; IMO, anyone who says it's lacking either has never really seen it in flesh and is going strictly on what has been posted somewhere, or by reading other test posted on the internet. I submit that, any round that will penetrate 16 + inches in ballistic gelatin will get to the vitals and therefore can be an effective round for self defense. The largest factors are gonna be speed and placement not so much caliber. And, those two factors apply to the larger calibers as well.