Weapon (d4)

One paladin erred – he was expelled from the order, he ceased to be a paladin, yet this entire group suffers from complete heresy – and they still remain paladins.

As was said, it depends on their own faith. Tirion (since we're talking about him?) was expelled, and he decided that he was no longer worthy to be a servant of the Light. But the brave Scarlet Crusade, the hope of humanity, a beacon of light in this heretical world yes, I know that their remnants were mercilessly defeated, were absolutely convinced of their own righteousness and therefore could use the Light however they wanted and for whatever purpose.

And the Blood Knights of the blood elves were also listed as paladins:

Well, they're cheaters anyway; they initially abused naaru, and now they've had Sunwell repaired for free, so they run around, pollute the air, and rejoice. It's not for nothing that they have earned offensive nicknames.