Barth is considered "Neo-orthodox", which is an intelligible label only in the larger context of liberal Protestant thought. That is anathema to American evangelical fundamentalists. The article you quote is an example of that, in fact: Barth was impure and therefore a false teacher. And vice versa.

Paul Tillich is viewed in the same vein, perhaps. He was however a seducer, an abuser if not an outright rapist. Barth loved a woman not his wife.