I lean toward your view of what he said. He has opted out of seeing the film. He made the point that he is an American, and his remark about being an "ex-slave" may have meant to say that he as descendent of slaves has done well in America.
He has distanced himselves from the other Hollywood types, and he took that opportunity to avoid criticizing America and the war. Obviously he hasn't been forthrightly for the war, he hasn't come out as a Republican and probably never will. But he is one of the few, now, to have avoided insulting the president, and he had the perfect opportunity had he wanted to. He didn't.
Perhaps his 'ex-slave' comment is more along the lines of being an ex-democrat.