I don't know your source for that, but none of the photos I've found show any Stealer player on the field to stand for the anthem, other than Villnueva. That includes the photo showing Villanueva standing alone outside the ramp onto the field AND an overhead shot of the entire field (with the large flag in the center) a Bears' bench area full of their players and staff AND the Steelers' bench area entirely empty of players.
