Any politician will tell constituents to march with him, get in line behind his banner, or some such metaphor. Calling it race war is overwrought.
The real story here is his contemptuous dismissal of their complaints as them being crybabies. It’s not in him to be otherwise then disdainful of friend and foe alike.
Context matters. When Obama gets 90% of the Black vote and now find it fragmenting and with the Tea Party called “racists” gain on you following HR elections of 2010, then the comment would appear colored with a “race war” metaphor.