And so the idea that who cares what people train so long as they are happy is thrown out the window.
Not in the least. I don't care what people train, if they are happy then it's all good however this is a case of someone telling us how to do something, and they are incorrect. If they want to train kata like that, it's fine but don't tell us that is the only correct way and everyone else is wrong.
You can use a hammer to put a screw in a piece of wood, I don't care but don't tell me that I must use a hammer and not a screwdriver.