I do think this no one should ever complain attitude is actually prevalent in lots of jobs : perhaps it is a British thing. Even at work, teachers are basically told any valid query, argument, complaint or dissent is 'moaning' and head nodders get promoted to SLT to squash the moaners.
People have every right to air criticism , complaints and frustrations. Or do you. like, Boris Johnson , believe it's all so much humbug and we should all put up or shut up.
I have never complained about my job to non teachers. We vent at each other, sure. Who doesn't?
I can't actually remember the last person who I spoke to about either their or my work.
I do however, in my long holidays, watch Wanted Down Under, which is full of plumbers, builders, nurses, social workers and many many other people form all backgrounds, wanting to leave the UK because they are unhappy in their jobs. Perhaps they moan at family and friends at home, too.