Peter Bergen has an op-ed in the NYT which starts with:
AFTER a terrorist attack like the one in Florida on Sunday, one of the first questions people always ask is: Why? Why would someone take the lives of innocent civilians who are total strangers? That is a question to which I have long sought an answer. But my search has led me instead to another question: Is an answer even possible?
He ends with:
No doubt we will learn more in coming days. But it’s unlikely that anything will ever really explain why he did what he did. Perhaps that says something about the nature of evil, — that it is ultimately not fully explicable. Even the perpetrators themselves can never really articulate “Why?” in any meaningful way.
Link:http://www.nytimes.com/2016/06/15/opinion/why-do-terrorists-commit-terrorism.html?

After recent reporting, notably that the murderer had been inside the venue many times before and the incoherent views expressed I am less inclined to think this attack was really Jihadist.