I may be an elemental embodiment of Law and Good, and no more capable of committing an evil act than you are of juggling anvils with your face, but that's my path, not yours. My path is not for everyone to follow, and I never seek to impose it on anyone. As long as you get to your destination eventually, you're alright in my book.
You see, killing, while an objectively evil act (and thus something I am usually not personally capable of), doesn't actually hurt you mortals. You kill a Good person, they go to one of the better afterlives, which are much nicer places than this cesspit of a Material Plane you've got going here, so you've done them a favour. Conversely, you kill an Evil person, they're immediately off to burn in one of the less pleasant afterlives, which is exactly what they deserve. And, of course, Neutral folks go to the more Neutral afterlives, which are about on par with the Material Plane, so it's sort of a lateral move.
So you go on, kill whomever you want, steal and rampage across the Material Plane. The bureaucracy of the afterlife has infinite capacity to get every soul to their proper place once they move on from the Material Plane. Including yours.
Now, if you were a vampire, or a lich, or a mummy, or a brain in a jar, or an illithid, or any of the other myriad perversions you folks have invented to avoid eternal justice, then we'd have something of a problem. All the abominations that clog up the natural workings of things and really tangle up the bookkeeping. Fiends rampaging all over everything on the Material Plane tend to muck everything all up, too. Never really quite seen eye to eye with the angels, either, though their hearts are usually in the right place.
- Lantern Archon Masuulael Lamakavodael ("Mal" to his friends)