Certainly, but when you're talking about a closing time of (at the drill distance of 21') 1.5 seconds how much "shorter" is there to begin with? Oh, and don't assume that shooting stops the action. (short of a CNS hit) Having hit the target is small comfort if they still manage to get a knife in you anyway before they go down. There's plenty of examples of people soaking up bullets before being stopped.
Mostly I'm challenging your "isn't much of a threat" assertion. If charged by someone with a knife/club/etc at even 30' you've got something like 2 seconds to make and act on a potentially life and death decision. I'm not calling a right/wrong on any particular incident but, as LG was pointing out, don't get too whimsical about what constitutes a potential threat.
