Shockley developed the first working bipolar junction transistor, which was the first transistor to ever enter mass production, which is why he's credited for it: https://en.wikipedia.org/wiki/Bipolar_junction_transistor

Though I'm unsure of the author's motivations, there's certainly a tendency with Shockley similar to what one sees with Hitler, where people will occasionally question or cast doubt on Hitler's WWI service record--which was by all accounts exemplary. (I.e., Bad Guy can't also possibly have done Good Thing.)