I don't dispute any of the factual or legal claims you've made. I even agree that a FOSS license is probably the best choice if the author's goal is to protect the user from the scenario where they turn evil and renege on their gift of code to the public.
In situations where I'm the author, this isn't always my goal. You know that Bernstein isn't going to go after his users, and I know that I'm not going to go after mine. Most users aren't going to be concerned about this possibility, either. Those who are concerned about it are likely to be for-profit corporations or their lawyers, and I'm not losing any sleep over making them nervous or losing them as users. I don't care to over-formalize things by invoking or even acknowledging IP law in my act of publication.
Each author's motives and goals are going to vary. It's not reasonable to enforce that "maximize assurances provided to user" is always at the top of the list for everyone.