Actually, it does. Because the DM is the final arbiter of the rules. They're the ones that get to define what, exactly, alignment means in a game, just as they get to decide what elven culture is like in any given game, or how a rogue's stealth works.But this doesn't automatically mean that the GM gets to unilaterally decide what the alignment consequences are of a given PC's behaviour.
Here's the problem. Good and Evil (with a capital G and E) are objective forces in the D&D universe. From a game standpoint, 100% non-subjective. That doesn't mean that D&D Evil is the same thing as real world evil, however. That's why we have rules and the DM to make hard lines between the different forces.
Now, lets say we have a setting where we take the Lawful Evil devils and make them a kind of necessary evil, where they involve things like sin-eating and focusing on only fighting / punishing evil in the world instead of causing it everywhere. You have people that worship the devils not for power, but making sacrifices for penance. Asmodeus recruits clerics and paladins that work as bounty hunters, condemning souls and sentencing them to torment in the old Biblical style. One can argue that they're a necessary Evil that is needed for Good to thrive. Entirely valid.
Its an objectively Evil force in the D&D world, but I don't know if I could call it evil in the real world sense.
Furthermore, the only times PC alignment comes up in play? It comes when interacting with NPCs and some magic items. Interactions with non-PCs is the domain of the DM. That's his job. Players don't get to dictate how NPCs see or react to their characters.
Yes, some players take it personally. Which is a problem on the player end, in my opinion - what happens to a character in a game world should never be taken personally. It is, after all, a game. That doesn't stop people, however. Sometimes, its best to avoid the discussion in the interests of everyone playing and having a good time (the most important part of the game).
That does not, however, mean the player has juristiction over how the world sees the character. He's (or she's) already had input on how his/her character should be seen by the actions the PC took and choices the PC made. Its well within the DM's rights to declare certain actions Evil. If the player persists anyways, even after they know, the choice was made, and now they're complaining about consequences.