While I haven't read any full length Domme memoirs I do recall reading 2-3 articles on the mainstream web (e.g. Huffpost) along the lines of "What's it like to be a Dominatrix". At least one was done as an interview.

Unfortunately our (alleged) culture has become thoroughly Oprahfied and so the whole "journey" narrative has become de rigueur.

If it were the mistresses who were complaining about describing activities I might guess it was because of the legal grey area pro domination occupies. But below you say it is mostly the subs. This mystifies me. You would think the memoirs would make good wank fodder, n'est ce-pas?

Now one possibility is the memoirs spell out sub misbehavior. The gropers. The guys who demand "happy endings". The guys who constantly try to get you to take your top off. The guys who try to extend the session time without paying extra. The guys who demand same day sessions. Yeah those guys. They might feel guilty reading about how the Dommes despise their antics.

My only other theory is the guys really deep into the humiliation vibe (I am not one) might feel that inside the dungeon the humiliation is Good Humiliation but if it gets in the public domain it becomes Bad Humiliation.