Because even as a Christian myself, I value truth or falsehood over us vs. them.

I do not see an ‘equivalence’ between Barton’s rhetoric and that of, say, Jeremiah Wright. Wright’s rhetoric is a reflection of genuine historical (and present) grievances, and IMO understandable perceptions on the part of many of ‘who runs things’ and ‘for whose benefit’. I don’t see how that same thing could be said of Barton’s.
(I’m not necessarily supporting what people like Wright say, by the way, but I do understand why they say it.)

Well, I resent it primarily because I believe this kind of behaviour brings Christianity into disrepute. If Barton is a Christian, he should focus on being a minister of the Gospel, and not a peddler of narrow politics.

To which tribe is he playing? To the Christian tribe?
And you resent that?
Why?

“He’s playing to the tribe …”
Well put.