Not the parent but I'll take a stab at this anyway. None of this is actually about moralizing, but very much about signaling that one is part of the cohort of "discerning" consumers (who wouldn't be caught dead, darling, eating a Red Delicious), and not among those great unwashed backwoods jerkwater hordes who eat them because they don't know any better. Hence the religion-like simplicity of the message "red delicious bad" which bears some similarity to a moral pronouncement while not actually being one.
Whatever. Red Delicious, Gala, even Mackintosh (remember them? usually for pie)... they're all good. Red Delicious is unfashionable, plain and simple. I find them great, when fresh. They get mealy/mushy when they've been sitting around too long.