Is there really a huge debate? I think I've observed runners, that have run for several years, falling into two groups:
Zen runners, those happy to run along at about 70% MHR often chatting away with a partner or checking out the birds, flowers and trees. Often they run up to 50-60 MPW, have an enjoyable time and finish a run metally recharged and ready to take on the world. While they get a lot of the cardiac and fitness benefits of running they don't necessarily get faster or win age group awards but generally don't care. And
Rabbits, those runners that generally have some success in their age group or even overall which inspires them to want to see how fast they really can go. Generally driven by that damm clock, they develop training programs for optimal speed and performance and often don't like a run that doesn't leave them winded. (Doesn't mean they don't have easy runs; they just don't seem to like them)
The marathon, unlike a 5K say, seems to draw both groups equally and you may see why they don't seem to get along. But I've never understood why members of one group feel the need to devalue the other. Often, for people that run over several decades, runners spend time in both groups (bicurious?) and switch back and forth over time.
The thing is YOU (any runner) have to determine your motivation and do what makes you happy. One of the best times I had at a sporting event was being about 1/2 a mile from the finish at Boston 2 years ago and cheering for the finishers and slapping hands. I was there for the winners and until roughly the 5 hour finishers and it was great because everyone of them was so glad to be finishing. I applaud the goals and successes of all runners but does it change why or how I lace them up? Not a bit.