Wow! I note that so far the Dallas police have not disclosed the man's picture or given any real details on him. That means, among other things, that we don't know the man's race, religion, or political background. (Although we can be sure that he is mentally unstable).
My gut reaction, though, is that this doesn't look like a guy from the black community angry over some police shooting or lesser incident. Those usually just aren't this premeditated. Nor does it look like Islamic terrorists. The motives are just too personal.
To me, this has very much the look and feel of someone close to the "Patriot" movement. Who else would own a semi-military van or be so eager to attack the core symbols of the state?
I guess we will find out soon enough if my hunch is right.