Your little voice is correct, based on what I've seen work in working in some capacity on 150+ handgun killings.
IMHO, the guy at the gun shop doesn't know what he's talking about, and probably hasn't seen a lot of handgun killings.
I've worked on cases in which penetration was a problem for .32 ACPs - if you must use the slow, light round, stick to the hottest European ball that you can find (S&B is good). Putting hollowpoint "brakes" on something so small and light is not a good idea when you need to penetrate at least to the vitals to effect a stop.
IMHO, the guy at the gun shop doesn't know what he's talking about, and probably hasn't seen a lot of handgun killings.
