I understand that, but TM wouldn't have illegally attacked GZ, If GZ didn't start to follow him and initiate the encounter. There are allot of what ifs, for ex if TM would have called the cops when noticed someone suspecious was following him, it would have had a different ending. TM's death for this exact incident would have not happened if GZ didn't follow him around. End of story. GZ put him self in that situation. Deadly force was IMO justified, but he put himself there.
And if he turned out to be a bank robber, he notices you are following him, he turns around and shoots you dead. Why would you put yourself in harms way, knowing there is a posibility he might be a BG, he might be armed, he might shoot you. I guess everyone will do what they want, but me personally, at the end of the day, I'm looking out for my family and myself. If someone in the bank was excersing their 2A, there wouldn't even have been somone with a skimask coming out of the bank(if indeed it was robbed). Following someone that looks like they just robbed a bank is just doing too much, I don't get paid for putting my life on the line. (all of this again is IMO, everyone has their own thought/opinions)