For instance a venue i worked at recently insisted on those at height wearing a hard hat and high vis jacket, neither of which helped
True, but poor application of the rules does not make the rules bad. That argument seems to be a diversionary tactic.
Safety should be about habit. You should always do the safety procedures automatically. If you leave it up to the individual to make a decision on it then chances are they will sometimes make the wrong decision.
Of course the individual can make bad decisions about anything, but I am talking about safety backup procedures.
I always put a helmet on when I ride a bike, even though I know sometimes I don’t need it, because I want it to be as habitual as putting on shoes or trousers. When it becomes completely automatic it’s no longer a chore, just part of biking.
Oh and one final thought – if I kill myself biking or climbing, it’s not only me that suffers, it’s my family. So the individualistic argument isn’t quite the whole story. I am responsible for not only my personal safety but the happiness of my family. That’s something I should not gamble with.