Starblaze thanks for your post, and your honesty.
I agree with you that MH is important, and also understand that it is linked to physical health. That is not really my point, though (I'll come back to this).
I also accept that neither I, nor anyone else, can know what someone else has been through, and that people have different 'thresholds', for want of a better term.
My point, though, is that in some cases people appear to 'opt out' of doing difficult things, and expect others to not only do their own share of these things, but to do theirs for them, and at the same time take the salary that is attached to having a 'difficult' job. This is the bit that I find unfair. If someone knows that they struggle with (as an example) public speaking, why take a job as a lecturer? There are plenty of roles that utilise other skills, and never require the holder to speak to a room full of people. By taking these roles, those who find them stressful are simply passing on the stress to others, which is, IMO, wrong. If a problem with public speaking develops whilst someone is in the role, then I think they should be counselled and helped however possible to overcome the issue, in the hope that there is no need to have to leave. Similarly, if some students don't have to give a viva because they are stressful, what about those who do give them and get a lower mark?
I suppose I see it in the same way as the fact that someone who is blind cannot be a bus driver, and if they develop blindness whilst in that role they would be expected to leave and be redeployed. It's not a good situation, but I suspect that few would argue with it.
I absolutely want to live in a caring society, but that has to work both ways, and people having to carry the can for those in jobs they can't do is not being caring to them.
This was not my only point, though. I was also (maybe clumsily) exploring the idea that letting people use MH as a 'get-out' (and I don't mean this disrespectfully at all), the issue of mental illness is trivialised, as more people will see what seem like excuses than they will, say, CPTSD, which, as you say, is often disguised.
growstuff, I didn't see your thread (or have forgotten it), but I understand that it is a difficult subject to discuss, as people can jump to the conclusion that anyone saying what I am saying is unsympathetic or lacking understanding, and I honestly am neither. I am just interested to hear what others think.