I think the big piece that is being overlooked here is the distance. The distance itself poses significant challenges. The obvious things like resupply and communication are much harder. But also the journey to mars is much harder on the human body.
Rescue and abort options are also much harder. The moon is close enough to easily resupply or rescue people on the surface, mars is much harder.
Rescue and abort options are also much harder. The moon is close enough to easily resupply or rescue people on the surface, mars is much harder.