This was hardly an execution. He was trying to lure officers in so he could blow them up, himself. This was an active altercation, not an intellectual puzzle you seem to be pretending it is. I have as much distrust and antipathy towards police in general as anyone, but I have to feel you are rather obtuse in criticizing police officers in a active confrontation with someone who has been targeting them and killing them at that moment, for actually fighting back instead of walking up and tipping their fedora and saying, pardon me my good sir, could you please stop killing us and let us take you into custody where we will ensure you get a fair trial. Umm...are you seriously this obtuse? You have every right to express how you feel but do you have a problem between understanding an abstract work of fiction and a situation in real life where the police's lives are on the line? I just can't believe you are criticizing them for fighting back?
This wasn't them targeting someone for no reason. They were being murdered by this person as this thing was going down.