FrogReaver
The most respectful and polite poster ever
So ... what exactly? A DM should never run intelligent NPCs intelligently? Evil NPCs need to always be politically correct so as not to violate a paladin's safe zone?
Because personally if a DM presents an NPC as an evil SOB, that's how I want them to be run.
A villain can be super intelligently evil and still not challenge the lawful good paladin with a practical solution that isn't lawful good.
Alternatively a very dumb villain could challenge the paladin with a practical solution that isn't lawful good.
Intelligence of the villain isn't what's driving the kind of villain and situation that's occurring - it's the DM. Thus the blame rests at the DM's feet.