Interesting discussion. I think the various arguments shows us, once again, that how people think is often as much about bias as anything else.
While there may be good reasons for tanking fuel in certain situations, my personal experience of it has been basically to burn extra fuel to save money on short to medium haul flights. There is also no doubt that a LOT of fuel is wasted by holding and early descents, at least in Europe. I remember being told by an RAF transport pilot that he remembered a ‘large scale’ jolly to the US to ensure that the current budget was used up, so as the next one wouldn’t be reduced.
I think its good practise to try and be thoughtful about the use of the planets limited resources, no matter what else we may or may not believe.