Even if the shooter happens to be white, it doesn't rule out known terrorist groups, does it? No, of course not, nor was I implying it did.
OTOH, we know that not all Muslims are terrorists, but all terrorists are Muslims. Also, not all Arabs are terorrists, but a disproportionately high number of terrorists seem to be, in fact, Arab.
I was agreeing with you because I think this is the work of Al Qa'eda or a related group. I was just saying that even if on the surface it doesn't fit the obvious description of Al Qaeda, I think it's still a good chance they're behind it.