Exclusivity and the potential downfall of the game.

[Fland]

But they do... My main job's relic weapon is BiS. I didn't look at the other jobs but I wouldn't be surprised if it's the case for more than mine.

People who clear the hardest content get the weapons that hurt the most, that's how it should be.

They probably meant during the time of their release. Relic weapons never outlevel raid weapons when the raid is released.
Relics would be BiS at the end of expansion when the raid is not so relevant anymore.