It offers a large hint as to which side they support.
They are pretty clear about it, aren't they?
I don't know for sure about the area in which this shooting took place, but is it reasonable to assume that it's in a restricted-access area? And if so .... wouldn't soldiers posted at Ft. Hood be a pretty reasonable suspicion?
Not saying that's what actually happened -- I have no idea. But it's not an "OUTRAGE" to as you so adamantly suggest.