Not true. This is from the RPG. RPG is not canon. The DH storyline goes back to War 3, but even much earlier (around the War of the Ancients). They can be only NE or BE for a reason.
I don’t understand is why are people obsessed with ‘every race playing every race’. These limitations are there for a reason and a good one. Let us not dilute the uniqueness of lore and history when you can just start an alt. Simple.