That was my initial reaction, but having looked into it, my understanding is it works like an extension of EGPWS, and so provided the runway is in the database ROPS will identify that you're trying to land on it and provide warnings as appropriate.
Yes, you're right - I've just found an Airbus presentation that says
"ROPS automatically detects current landing runway using terrain database"
It goes on to say
"If the detected landing distance available is assessed too short, ROPS triggers an alert to encourage the crew to apply and keep all available retardation means"
I suspect that in this instance, no such encouragement was needed.
