Is it true that cancer, functionally speaking, is a metabolic disorder and not a genetic one in terms of its cause?

This is very true and is an extension of many workers who have hit on this idea down through time but become discouraged, particularly because of the inertia within the field itself and the fact that there is so much rigid thinking, a kind of collective herd instinct. That is no accident because it is managed to be that way. This you witnessed yourself as a cancer researcher newly entering the field and being struck at how different the energies were, compared to working in other arenas such as transplantation and immunology. What you were sensing intuitively, was the group-think being orchestrated through mind control, so new ideas are resisted heavily and mightily by all the established scientists. There are ideas and hypotheses that come and go, but novelty is routinely and roundly rejected because of preconceived ideas. So, once on a path, everyone focuses on it for the most part and will not consider anything new but only further refinements and deeper investigations into the approved approach and not thinking about the fact that such approaches do come and go and become, in effect a passing fad. But at the time, all embrace it readily and run with it, and this keeps the field sidelined most of the time because they are simply pursuing a series of faulty ideas and wringing the last bit of non-confirming evidence from each one before allowing something new to be embraced. This is wasteful and inefficient at a minimum, and negligent, foolhardy, and self-destructive at the extreme that we are speaking of here. That is the norm. This has never been truer than the infatuation with the idea of genetic alteration being the cause of malignancy and having so much collective effort in mapping the genome of tumor cells, and looking at the many, many, levels of regulation controlling gene expression, and the epigenetic influences, as well as any other potential source of dysregulation that could lead to faulty genetic response. At a minimum, this is misguided but in actuality it is yet another of purposeful misdirections done in a series of faulty notions that do come and go but take years to be worked through, only to be rejected in the end from the lack of progress, and the field becomes stymied, having explored every possible avenue and detailed probing without bearing fruit. So this has been the case since the time of Warburg who was championing this idea back in the 1930s and was correct in his projections but did not have all the tools needed to provide definitive data. It is still questionable whether it would have mattered, because at that point in time the field was already being constrained and the idea would simply not have been allowed to be a point of focus to be pursued heavily, and in fact this is what happened. The idea is resurgent once again, so time will tell if things are any different. In any event, we can tell you that the dysregulation of growth is a metabolic problem and not a genetic one.