It made me carefully evaluate why I want a pond. The answer really has more to do with what I don't want.
I am primarily a gardener and creator. I love gardening and I love the constant stimulus to my creativity that it engenders. For me, a swimming pool is an ugly thing. It's a barren, sterile, chemical filled hole that offers no reward to me or my family. In fact, it's a pain in the arse to keep clean.
Converting my pool into a pond is not with the intent to keep koi. Not at all. It's to bring beauty into that corner of my garden, that my wife and I can sit around with a glass of wine and have a slice of peaceful nature.
My aim is to create tranquil interest, and for that I need at the very least, a healthy pond with plants in it and preferably clear water. I am prepared to forgo fish completely in order to have clear water. Together with this aim, my power consumption needs to be minimal. My power budget should ideally be less than 150W. It wouldn't sit well with me to have something natural and beautiful knowing fullwell that it is munching electricity and creating pollution elsewhere.That, to me, misses the point.
What use is keeping healthy, beautiful fish in your back yard (and proclaiming to all who would hear) what a wonderful, nature-loving, tree-hugging animal fancier you are, when you are drawing 50kw a day that comes from dirty coal and destroys nature, just not in your back yard?
Be that as it may, the day might come that I would like to try my hand at keeping fish outside. Just because it would never be my primary aim, does not make me any less suitable as a fish keeper. I don't know my kamikazis from my hara kiris and bukkake showers, and so what? One does not have to be passionate about koi to the point of pedantry in order to love them and care about their wellbeing. (the 50+kw some okes are using per day are more telling of an obsession, and that's their prerogative after all if that's what they want). It's nobody's business.
My needs and wants are different, and I'm mature enough to know what they are and not be bothered by not being 'a true scotsman' as the OP would paint it.
If there is a distinction to be made, it's the same as in any expensive pastime, whether it be scale planes, bikes, boats or bakvissies: willful ignorarance is to be criticised above all other things, and it is definitely not guaranteed that 'passionate koi KEEPERS' are immune to it, is it?