An instructor with ethics won't set out to humiliate anyone. Squeeze and pressure at selection time is a fair cop, as long as it is applied according to the level of the candidate. If I apply for a DEC, I am saying in effect to the would-be employer 'hey, I already have Captain skills, just maybe not in your aeroplane type. Try me, apply a bit of heat - I want to prove to you that I can cope and meet a reasonable Captain standard.'
Now, if the sim guys are assholes and go way over the top, I will fail for sure. Or decide for myself that I don't really need the misery of having to work under that kind of check-to-fail culture.
If I apply to be an entry level F/O. I expect that the sim guy will look at whether I have assimilated the basics according to the hours I clain to have, and whether their training programme can provide in a reasonable time and at a reasonable cost, what they expect out of their RHS pilots.
There is no place in aviation for smart-ass instructors who expect perfection from the first hour in the simulator just because they have had years of practice at it and thereby have an advantage over the average pilot. Or who seek to use simulators to load pilots to breaking point. Or who can find fault just for the sake of it.