Is poison use evil?

[The Random NPC]

Honestly, I do not see it as stupid. If you treat taking levels in Assassin as joining an in-world group, a conceit common to many prestige classes, then ffones explanation makes perfect sense. You don't like the idea of having a character killing someone merely to join a group but have the assassin abilities, then become an Avenger.
No, not that kind. Nor that kind. This kind.

I belive Coidzor's point is that on the one hand you have some guy that already knows how to kill people and wants to join your group, and on the other, you have a guy that shanked a starving street rat in some back alley who also wants to join. One of those is more worthy of joining, but mechanically they both get accepted. If they were trying to make the class an orginization, the orginization should be giving you your first assignment. If not, you shouldn't have to kill someone to join the class.