I don't know, Goebbels was a doctor. I read The True Believer several times when I was young. I was mightily impressed with it. I am less so now. The trouble with Hoffer is that he seems to suggest that anyone who joins a mass-movement, that anyone who tries change outside of establishment rules, is mentally ill or emotionally deficient, and that we should all just mind our own business and pull our own little yokes and let the powers that be, the natural leaders take care of the big things. It is coolie philosophy. Lay down and take it because nothing ever really changes and who are you to challenge the elite, anyway? Hoffer is good for a soundbite, and has many interesting and thought-provoking ideas but overall has to be taken with a grain of salt.
Everyone should be read with a grain of salt, but I don't see Hoffer as saying we should all mind our own business -- instead, to beware of how mass movements are driven