no one here knows for sure. I don't see what incentive Gruden has to not spill the beans and say he was forced out but I generally think what you are saying is true.
The broader point though is that he's not facing any legal action as a result of his behavior. He is no longer employed. Watson is facing legal repercussions and if he is guilty he absolutely deserves to be thrown in jail and lose more than just his NFL career.