He's right, depends on the situation!
Having sat at the runway in Beijing once for over an hour, after already having waited at the gate for an hour due to a slot, we pretty much used up al our cont fuel ( even with two engines shut down) sensible to just go and closely monitor fuel in the air. Rather make a pit stop in HEL or even CPH than to go back to the gate, refuel, wait for another slot and wait at the runway again!
So that was legal and sensible.