If it was just from an argument, then how do we have so many casualties and injuries?
I don't make up the news, just repeating what I've heard/read so far. The left would say because he snapped and just started shooting.
I don't know what really happened, so there's no real way to answer your question. We're all just waiting for answers. I just wanted to point out that while we wait, we shouldn't jump to any conclusions ourselves.