Oh...that's all. So let's ignore for just a second the logistical advantages of figuring out how to actually mount a manned mission to build something non-trivial on another body when you're 3 days away, not 6 months away. Pretend that isn't important.
The moon has water, raw materials, enough gravity things don't just float away, abundant solar and we've already figured out how to get people there and back. We already have an MVP to build on.
On the other hand, a manned Mars mission is still an un-funded wank-fantasy with a disturbingly high failure rate for the unmanned attempts.