Exactly. When you're a fighter, and you say "I move and attack", nobody goes "you can't do that, you can only full attack". When you roll the dice to see if you hit, there is no confusion about it, and if there is, you just have to quickly re-calculate to make sure you're getting the bonuses right, it still has a definitive ruling. Meanwhile, alignments have no mechanical effects aside from tags and effects on certain spells.
We could decide to replace "good, evil, law, chaos" with "blue, orange, green, red" and remove all the flavor text and it might actually be an improvement. Except for the part where it doesn't say how many times you have to use a spell with the "orange" tag before you aren't blue any more, or anything like that.