Actually I would say it DOES matter. Are there occasional unjustified shootings by the police? Yes, there are. Are “most” police shootings unjustified? No, they are not. Almost ANY crime, including rape and murder, will usually receive far less than the death penalty in a court of law. Do does this mean that the police (and I assume you would also extend this to citizens who act in self defense) should reserve the use of deadly force for only those suspects who are likely to be serial killers?
This case is the exception to the norm, and to try to generalize it to represent even a substantial portion of police shootings, let alone “most” police shootings is every bit as disengenuous as the attempts by the gun-grabbing brady bunch to pounce on every gun crime as a reason for more gun control laws.
Are “most” police shootings unjustified? No, they are not.
I'd say that the prevalence of questionable shootings these days makes that issue a lot more murky than it used to be. There's a definite "shoot first, ask questions later" mentality that cops in this country have adopted in the name of "officer safety" and it's led to more guns being used in circumstances where they probably aren't justified or necessary - e.g. conducting a SWAT raid on a small-time marijuana user, or "disarming" an angry granny with a kitchen knife.