If someone grew up Frum and went off (which I think is what happened to CP if I’m not mistaken. I think he went to YU, since I think I remember my father saying that he recognized some of the people/Rabbanim in his books. But if I’m mistaken about CP’s background, feel free to correct me), it would seem likely that his perception of the Frum world would not be completely accurate or positive.
I think the main problem that people have with CP’s books is that the point of his books (or at least one of the points if not the main one) is to present his hashkafa and from what I understand, his own hashkafa may be off.
I am speaking in general terms since I read the books too long ago to be able to comment more definitively.