This is probably one of the most commonly-used fallacies I see people used to deal with cognitive dissonance caused by information that might make them uncomfortable.
I mean to get through life without having to run every single thing down you use heuristics to evaluate whether it is worth pursuing the details or not. My heuristic wrote off whether looking at pursuing his perspective is worth it or not based on the comments in his twitter feed which seem to match up perfectly with his charges. It's why credentials have value.
I don't know what's on his twitter feed, but I've yet to see a single rebuttal to any of the main highlights of that book. Don't be blind to the truth because of your own personal biases.
I just scanned his twitter feed and I don't see anything terribly problematic, so I'm not even sure what you're referring to that would make you ignore him.
This is probably one of the most commonly-used fallacies I see people used to deal with cognitive dissonance caused by information that might make them uncomfortable.