Oh boy, am I triggered! I recently spent some time looking for a new job and went through a number of terrible interviews that involved psychological behavioral assessment tests.
I don't think it was a coincidence that all of the really bad interviews/companies I've had also made extensive use of psychological evaluation/behavioral analysis questions. These things seem to go hand-in-hand.
To directly answer your question, I think the real intent behind behavioral questions is that there wasn't any intent, or much thought. People who ask these kinds of questions often ask them because they just googled for things like "how to conduct an interview", and "questions to ask during an interview". They found websites with examples of terrible psychological evaluation questions, but they don't really know why they are asking them or what they were supposed to get out the question.
What your are seeing here is monkey mimicry. Look at all the companies and hiring managers that have been mimicking what they think is great advice they got from how Big-Company-X (google/facebook/stanford/et-cetera) about how to hire great people. Remember all those stupid brain teaser tests?
In the few cases where some train of intelligent thought lead to someone asking these silly questions, they usually just want to push you a little to find out if they can make you snap easily, or get frustrated. This is an important and desirable trait in abusive workplaces because the employer doesn't want someone who is going to raise their hand and say, "excuse me, that's not right". Of course, it's important in good workplaces too, because they don't want someone who is overtly aggressive or displays an inability to be flexible in stressful situations, or gets easily flustered.
Think of the scene early on in the movie Blade Runner. (But try not to think about the fact that the position being interviewed for was a waste disposal job). Don't pull a Leon Kowalski in the interview.
The hiring process is a sieve; a gateway filter. What kinds of people are being let through, and what kinds of people are being filtered out by this style of hiring process? Paying attention to this will often gift you an awful lot of insight into how the company operates and what kinds of people you would potentially be working with.
There are other, more clever, ways of figuring out the behavioral profile of a potential worker without subjecting them to an abusive and insulting interrogatory, but they almost always take more time and effort, and really, who has time for that?
The most significant problem I have with psycho analysis questions is that if the interviewer is not qualified to interpret the results of their experiment, then that's a serious problem. And, how many of the HR goons you've met do you think have a degree in psychology, or have been training in interpreting the results of a psychological evaluation? None at all ever? Yea me too.
It's not entirely their fault. Hiring people is really hard! Even if you do put the candidate through a series of exhaustive tests and have qualified staff to administer and evaluate those tests, the result is still that sometimes it just doesn't work out, or the candidate ends up leaving for a better job after a few months.
For me, I turn the whole situation around. Behavioral analysis questions are a valuable source of information about the company. They are usually a display of mediocrity and thoughtlessness (but not always!), and those are usually not the kinds of organizations I want to work in.
If an interviewer asks me "Tell me about a time you got into an argument with you manager.", I like to turn it around at them and watch how they react: "I don't make it a point to get into arguments with my co-workers. What happens at work is business, and I don't let it get personal. But it really troubles me that you are so terribly concerned about conflicts in your workplace. What is going on in your organization that is promoting this kind of behavior between staff?" "What kind of manager promotes conflicts and argument rather than engaging in de-escalation and consensus-building, and is that the kind of management I should expect to be working with in your organization?"
The above is written a little aggressively(it's all about the in-person delivery), but doing this has it been super effective for me. People don't realize that they are projecting the toxicity and problems of their workplace in their questions.
At the very least, when it's all over, ask the interviewer why they were asking you these questions, and what they expected to get out of it. If they don't have an answer or seem offended that you would dare ask, then you've got your answer: RUN AWAY.
Remember that behavioral assessments are evaluating:
>Communication/verbal skills
>Listening ability
>Attitude
>Ability to play the submit-to-my-authority game
Good luck in your next interview!