No, it says that you must or the RA fails. It doesn't say that you get to because of it.
So when Confused says opponent "must" discard a card from hand or battle, that's not a discard ability?
When United Army says all warrior class Heroes "must" the battle, that's not a banding ability?
When Tears for a Friend says that all players "must" reveal their hands, that's not a reveal ability?
When Herod the Great says Heroes "must" return to their territories, that's not a withdraw ability?
When King Abijah says opponent "must" give holder an unoccupied Site, or discard a card from hand, that's actually only a discard a card from hand ability?
Is that really the price you want to pay for assuming that "must" somehow turns an ability into not-an-ability?