> one of the doctors, when she saw my shock, took me apart and explained that this behaviour, so shocking it might be when seeing it for the first time, is part of psycho-hygiene that allows the people to be able to continue to work
Did you consider that her taking you apart and explaining it away with that excuse is just as much part of her "psycho-hygiene" that allows her to joke about the suffering and mental well-being of the human beings explicitly left in her care, without feeling bad about it?
I mean, what the hell? I trust my therapists not to laugh about my issues behind my back just like I trust the chef cooks at a restaurant not to spit on my food. Even if in most cases I won't be able to tell, it's a matter of trust and professionalism. I have to trust them on this. I HAVE to be able to honestly believe that a therapist or psychiatrist with a professional attitude and ethics will NOT joke about the most embarrassing issues I trust them with, the moment that I turn my back. Otherwise you can't do therapy with them.
Therefore whatever the hell this doctor thinks they're doing, is very unprofessional.
No matter the excuses they told you. I mean if you need this sort of disrespectful "psycho hygiene" for your mental well-being, first consider if you're even cut out for the job. Maybe look for other parts of the mental health sector, with patients whose problems you find less hilariously funny. Finally, if you really found your calling in one of the rather serious, dark corners of mental health care, the ones that are truly as taxing that merely working there requires counselling lest you burn out, then do exactly that. Vent at a counsellor. You can even joke at them because they're bound to a professional secrecy. Your colleagues aren't. They may be to your patients but not to you and that's the point. It needs to be separate.
And also VERY importantly, that counsellor will tell you when you actually cross the line and venting turns bad. In a social group, between colleagues, and a psychiatrist should know this, there is no such check. There's group pressure. Boundaries are tested. Someone says "maybe that's in bad taste", but next week two other people do it, and the someone doesn't want to keep nagging at colleagues, so the behaviour gets normalised. Boundaries have moved. Now you have a proper toxic environment. And then at some point, a young new 20-something staff-member joins, is shocked about the lack of professionalism. Now they have to be taken apart and explained why this behaviour is considered okay and is normalised. But says who?? There is no oversight, no checks, it's just social pressure and venting between colleagues. Who's there to say "this is enough and this is too much" and how are they qualified to make an objective call about it?
Just out of curiosity, what country's mental health care were you talking about? The quality of that varies widely enough that sure there's enough places in the world where if your story is the worst that is going on, it's probably good and at least it's not neglect or abuse. It's a matter of how high you put the bar. Regardless, a psychiatric doctor shouldn't actively rationalise this behaviour to newcomers.
Quickly getting back to the BDFL topic: There are many ways to handle pressure etc, and the ones that do not require you to occasionally "explode at someone", are in fact healthier and better for one's mental well-being.