I'm not a Second Amendment supporter, by and large. I think it's poorly written and outdated. However, it is the law of the land. That's something many people still need to come to grips with. Those saying "the shooter shouldn't have brought a gun," or similar nonsense, are living in a dream world.
In reality, people are going to carry guns. Our best hope is that those who carry guns will buy, sell, carry, and discharge those guns in a lawful and responsible manner. According to all information I've seen for this case, the shooter did absolutely everything he was supposed to. He didn't start the fight and he didn't escalate it. He also didn't fire a single shot until an angry, intoxicated, and threatening man charged at him at full speed (after the man's friend punched the shooter in the face with zero provocation).
Don't get me wrong: the fact that the attacker later died is terrible--though it should be noted that he died not as a direct result of the gunshots, but because he and his friends were driving while extremely intoxicated and rammed into another car (involving even more innocent people--who were hopefully unharmed--in their fuckery). But his death is just the epilogue to a story that started when he and his friends got drunk and high, then decided innocent people needed to suffer the wrath of their blind racism and impotent rage.
Tldr: he didn't deserve to die, but he absolutely begged to be shot. I mean, really, who charges head first from outside a building back inside to get at a man holding a gun?