If the "Fuel Shutoff Valve" is ON, wouldn't fuel be cut off?
I can see where that can be confusing, but it comes down to perspective.

From a maintenance and engineering perspective, you are actuating the fuel shutoff valve which controls the fuel to the engine.  The actual terminology when referring specifically to the valve would be opened or closed, which would result in the fuel being on or off.

From a pilot perspective you are simply turning the fuel selector on and off, which happens to be connected to the fuel shutoff valve.  The pilot doesn't even need to know about the valve, so they placard it from the operational perspective in the cockpit and say whether the fuel is on or off.



Note that these are placarded as a fuel selector and fuel off both of which seem pretty clear to me.