How did we go from Moon vs. Mars To LEO vs. Mars?

I really don't understand your question. Based on the repeated use of the word "vs", you seem to be framing it as if I see these things in opposition. I don't. It never has been "moon vs. Mars" to me, nor "LEO vs. Mars."

I see LEO as the staging area for trips to anywhere, including Mars. If, and this is a fundamental "if", harvestable resources exist on the moon, then I see the possibility of reducing the amount of materials that have to be launched from the Earth's surface. Given that launch costs are so high, cutting the amount to be launched from the surface by a factor of 3 (or more) could have real economic benefits.

To the greatest extent possible, we need to use the resources in space to further explore space. This is certainly true for Mars and may well be true for the moon. However, it takes far more than propellants and consumables to support space missions. It'll likely be generations before an infrastructure exists on Mars to do much more than refuel spacecraft. Real infrastructure is the ability to produce all of the materials needed for missions, from soup to nuts. For that, we're still bound to the Earth where the skilled people, the machinery, and the primary resources reside.

In the 6 Apollo missions, we explored at most a few square kilometers of the lunar surface, which has a land area about equal to Africa. There's a lot of unexplored territory there. In addition, it can make a good testing ground for space systems and habitation techniques that would be useful on Mars. Finally, if the moon has harvestable resources, there's the possibilty to use those to support many other space missions, including (and especially) Mars. Not from the lunar surface, but from LEO.

Doing this will require some vehicle development, perhaps unmanned. It might make the most sense to have a vehicle designed to ferry supplies to and from the lunar surface and lunar orbit, and another vehicle to operate between LEO and lunar orbit. Aerobraking at the LEO end would be a good idea to reduce the propellants needed to enter orbit. This vehicle might be designed to carry a sizeable payload between LEO and lunar orbit, say 50,000 pounds. For the outbound trips, it could carry supplies for the people on the surface. For the return trip, it could carry water or ice, which could be processed in LEO to provide propellants and consumables (water and O2) for use by space tugs and manned spacecraft bound for places like Mars.

Like I said, I don't see this in an adversarial light at all. I see it as LEO AND the moon AND Mars AND the rest of the solar system. I don't see it as an "either-or" proposition.