why do we need to wonder when things are well made if we're going to explain away anything that we don't judge favourably as "we poor mortals cannot grasp his g

why do we need to wonder when things are well made if we're going to explain away anything that we don't judge favourably as "we poor mortals cannot grasp his greatness and thus cannot really that this is indeed an instance of bad design". Why would we mere mortals be capable of knowing good design when we see it in the first place?