The New Yorker’s Susan Glasser says Ben Carson’s gushing praise at a 7/17 Cabinet meeting “did nothing to halt the accusations that the President is an unreconstructed racist.” In this context, I'm thinking that's the wrong word. It means "not reconciled or converted to the current political theory or movement," but what current theory makes racism look nice? I’m thinking she meant “unreconstituted”—like a mouthful of lemonade concentrate

I think it is one of those lazy journalistic words that they use to make it sound “better”. The sentence would mean precisely the same if it were removed. It usually seems to mean something like “old school” or “old style”.