It is? Honestly, to me that's just a line Dumbledore throws out that's never really dramatized at all. Except to have the characters imo very often choose easy over right and never look back on it or face any consequences for it that makes them learn from it.

Then, what of Sirius's death? It seems to me, especially in Order of the Phoenix, that Harry learns this lesson in a pretty drastic way. I'm not suggesting they all get their comeuppance for every moral transgression. But again, I think one of the series' major points is that this kind of moral legalism is far too reductive.

~Dave the Longwinded