He mirrors the professor, resorts to the extreme right-wing Guido Fawkes - then calls a perfectly sane academic "barking mad."

Two things. That was a response to a post from Iains that appears to be no longer here. The sentence is a list of three items, the first two separated, correctly, by a comma. I neither wrote "He mirrors the professor by resorting to an extreme right-wing website...", nor did I intend it to mean that. Had that been the intended meaning, the sentence quoted above would have been highly ungrammatical. I could spend half my time here correcting deliberate misreading of posts. Ah well.