"That's interesting; given that a rook is allowed to move sideways from 4 onto b4 and beyond, that means that a rook on 4 can threaten a rook on b4 without being attacked back. Is this intentional?"
That doesn't seem logical indeed.
Assuming a rook is on 4 and an opponent's rook is on e4, my definition means that the rook on 4 can attack the rook on e4, but the reverse is not possible. That's inconsistent. It is probably appropriate to add that the switch can be operated not only from 'below' but also from the side. This would eliminate the inconsistency.
"That's interesting; given that a rook is allowed to move sideways from 4 onto b4 and beyond, that means that a rook on 4 can threaten a rook on b4 without being attacked back. Is this intentional?"
That doesn't seem logical indeed.
Assuming a rook is on 4 and an opponent's rook is on e4, my definition means that the rook on 4 can attack the rook on e4, but the reverse is not possible. That's inconsistent. It is probably appropriate to add that the switch can be operated not only from 'below' but also from the side. This would eliminate the inconsistency.