That can’t be right. You must have read it wrong.
Because I did the BE heritage armor quest on my DK. VERY good quest series, I highly recommend it. It wasn’t just “collect 8 rabbit pelts”, it was a great history of the Race. I never knew there was a statue of Sylvanas there! lol
Anyway, I recently made a DH and… sure enough, the BE heritage armor is available to him.
You only have to unlock it ONCE. There are enough restrictions in place without thinking you need to grind it on EVERY chr that wants it.