I am not arguing that emotions immediately disqualify anyone. That would mean we'd all have to act like Mr. Spock, which is silly. It's what you DO with your emotions that matters. Recognizing when they are either leading you towards truth or away from it is an important trait.Training oneself to think rationally does not mean emotion gets abandoned, it means learning to put it in its place.
Comparing similar things does not mean they are the same. For instance, a triangle a mile high is considered to be similar to a triangle an inch high, if their angles are the same. Obviously one towers over the other, but the little one is still what it is.
Also, the timeline or sequence of events has meaning in the context of this event. If the gun came out before the shove occurred, the shove (and much more) may have been completely justified and legal. But that's not what happened. The shove occurred first, it was "first blood" if you will. That DOES NOT justify lethal force, but neither does the shooting absolve the the deceased of the fact that he struck first- a fairly clear-cut assault.
A good example of emotionality possibly leading me astray. Although it's probably best not to attract negative attention, I find being ignored slightly disrespectful. So here I am, lol. Fire away.