The video is bonechilling, and from what I understand the clips being dispersed across the web are only segments. I am posting TMZ's video because it shows the face of at the very least the "woman" recording it.
I'm not an expert, I do not know shit about psychology, antonomy. I don't know what is wrong with those people but I do know that people who commit disgusting act like this are not singular aparitions. People like this are prevalent. These four or more, 18 year olds may plant some meaningless idea or justification behind it but regardless of whatever name they yell as they pull the trigger of intolerence and hatred, it never changes that they are terrorists. They are using fear to propagate their ideas, which is the definition of terrorism. It doesn't matter that they let the man live, whoever was involved in this crime is no better than ISIS, than Osama Bin Laden, Al Queda, or Guy Fawkes. You don't have to subscribe to a certain religion to be a terrorist. The color of your skin has nothing to do with. What determines the difference between a terror mongerer and a civilian is the wiring inside of the brain. For as long as humans have recorded history, there have been people willing to use terror, destruction, murder, and fear to cause change or establish power. So again, my point is; there are, have, and will be people like this. Ones whom for whatever reason choose to submit themsevles to cruelness.
I could keep going on, writing about why or how people get or are born that way but I really only have extreme speculation and a wild imagination. I can't offer anything useful. The only thing that people, like you and I, can do is learn these peoples names. Not so that twitter, facebook and other social venues can turn their families lives into hell. But so that we can indentify these ugly people before they are forgotten in the deep darkness of the United States prison system.
Not to continue to spread bad vibes but really hope the federal government charges them with domestic terrorism.