You guys need to do some heavy reading on the subject of terminal ballistics. The goal of self defense ammunition is not to get stuck in the bad guy and be hard for the doctor to get out.
The goal of self defense ammo is to penetrate the vitals of the bad guy and expand reliably, but to expend its energy on the bad guy and not pose a threat to anything behind the bad guy. Good self defense ammunition still penetrates and expands in the bad guy the way it's supposed to even after going through a barrier.
Why people tout a lack of barrier penetration as a preferable trait in self defense ammo is beyond me. Walls, glass, interior doors and car doors are all barriers that you may need to penetrate to get a good shot on the bad guy if he's taken cover and is shooting at you.
Here's a good a short article written by a guy who is a radiologist to get you started.