so, why do banana peels taste like shit? is it proof that they're not worth eating?
maybe if you're a creationist - if you think this world exists around us for our benefit. then, god would make things we want to eat taste good, right? therefore, we should avoid vegetables and eat more candy.
in fact, bananas no doubt evolved to have a bitter outer shell to dissuade animals, like birds and monkeys and humans, from eating them for the precise reason that they are, actually, nutritious. evolution doesn't generally invite us to do things that make sense, like a deity would; rather, evolution tries to trick us into doing stupid things, to ensure the survival of other species.
if they weren't healthy, nobody would want to eat them, and they wouldn't taste so bad.
it's a better argument than "monkey see, monkey do", anyways.