Just because you're a dope dealer doesn't mean you lose self defense rights. If someone who is not a cop breaks into their house, self defense still applies. And, unfortunately, if a police officer is shot because he did not identify himself and was not readily identifiable for any reason, self defense applies.
Thank God you guys do what you do. Seriously. I don't envy you, and I respect you. But just because you're a cop and someone is a criminal doesn't give you free reign to do whatever. And I am not, I repeat, AM NOT stating that the police in this instance did anything wrong. They may have done everything right, and if so, fuck the guy who shot him. But we can't just assume that because procedure says X, then X was done. We don't start shouting inaccuracies about how it was broad daylight to defend a cop just because he's a cop. We should be defending who was in the right, not who had what profession.
Again, if what the cops did was done correctly (and as you alluded to, in most instances they are), then fuck that guy. Even if a procedural step was missed, but it can be shown that he did know it was the cops, fuck that guy. But I'm not going to prematurely decide who's in the wrong when there are unknown facts that may decide the issue.