One of the outcomes here is that you can purposefully place yourself in harm's way and still claim and win a self defense argument.
He was at a business posing as an anti-riot/looting deterrent with an AR15, backed by the police (who were arresting others violating curfew) and the owners of the business.
So no matter what position you place yourself into, you always have the right to kill another if you are fearful of your own life being taken, regardless of circumstance.
It is gun culture, vigilante justice, systemic racism, and a failure by the police who are complicit in these killings. The cops saw Kyle as an ally. He acted as an extension of the police show of force without the restrictions of being accountable to or acting within the expected behavior of the police force.
The AR15 open carry is an overt display of force. If I saw someone open carrying an AR15 I would get the fuck outta dodge. It is hyper aggressive behavior.
I expect it to become more popular than it ever has been.