It's just who they are.There are many kinds of snakes that make great (docile) pets that are NOT finicky eaters, so the real question is, why do people keep CHOOSING ball pythons, knowing full well that they are finicky? It reminds me of a saying (sometimes credited to Albert Einstein but never proven): the definition of insanity is doing the same thing over & over again, but expecting different results...
(-as I duck & run for cover!)