If a station was put at the L point above the Moon, it would be at the top of the Earth's gravity well, and thus have very little Moon/Earth gravity to contend with. Launch ships with just enough fuel to get there safely, then fill them full of fuel there. That way, they would start out with a full load to get to Mars/et cetera. Also, with not having to overcome so much gravity, it wouldn't need as big of load of fuel to get to Mars, and the weight saving could be swapped for cargo.
Also, at certain times when everything aligns in the cosmo, you could fuel at the L point, then head for Earth to pick up speed and slingshot around Earth for an extra boost of acceleration to Mars/et cetera.

But all this is based on establishing a base on the Moon to have the infrastructure to make fuel from the water there and get the fuel up to a docking station at the L point.

It's all a matter of doing it.

From the looks of the shape society is in, I'm not holding my breath, even if I could.