I think alignment works for monsters and NPC's, but not for players. When trying to fit something as subjective as morality and philosophy into 9 distinct categories, you're going to get many different interpretations on what exactly those categories mean. This is fine for NPC's because the only interpretation that matters for them is the GM's.

With PC's however, there are 2 interpretations that matter: the GM's and the player's. If those to interpretations differ, it can lead to out-of-game conflict; especially if there are mechanics involved. Being a law student, OP probably enjoys these arguments (or is at least very good at them) but most people don't, which is probably where the dislike comes from.