I cannot speak for the others, but the reason I am advising them to use another model to learn on is because the model he is building has been long out of print and is basically irreplaceable. Additionally, it is not as stable as a trainer. And do you always assume that any old instructor will do? Just because somebody says "I are an instructor" doesn't mean he is any good, etc.

My point is, why should he risk tearing up a neat sport model that he's spent months building, when he doesn't have to? Sure, he'll have to risk it eventually. But at least give the model a chance by learning to fly first...