Refueling on the Moon was debunked decades ago
Back in the 1950s and 1960s, papers were written in ACTA Astronautica and other journals debunking the notion of using the Moon to refuel spacecraft to Mars. Supposably even if there was liquid hydrogen and liquid oxygen pooled on the lunar surface, it still would not be energy efficient to go down their, siphon the fuel into the vehicle's tanks and then fly away. Bush's reference to this old chestnut indicates one or some combination of the following:
1) He and or his advisors don't care.
2) His advisors are ignorant.
3) His advisors are not being truthful.
4) He and/or his advisors are pursuing a hidden agenda.
I rank 1) as the most likely explanation followed by 4).
Gary