The economists call it "Opportunity Cost" and all that. The opportunity cost of space exploration is kinda high, and humanity's resources are limited. I like space probes and space bases at least as much as the next citizen of the world, but they're not my priority.
1.) Don't shit where you sleep. 2.) Don't put all your eggs in one basket.
As a species we really ought to stop doing both of those...
Reiterating, not putting all our eggs in one basket ie self-sustaining human populations not on Earth in the shortish term, not in our solar system in the less shortish term, and not in our galaxy in the longish term, is not something a single person is going to do in their lifetime. It may take (tens/hundreds of) thousands of years to accomplish these goals, if they are even possible, but we should start them now because the alternative is a random case of bad luck with a meteor, or a nutter with a thermonuclear or biological weapon, or whatever. Extinction events.
People struggle to see beyond their own needs and desires. If we're to survive as a species, we have to think and plan on time scales that dwarf the current recorded human history.
This isn't meant to be an indictment of you personally, I'm just pointing out that the view-point, though normal and held by the majority of people, is still short-sighted by definition: a human lifetime is nothing in comparison to human history, and the potential human future.
Building a Moon base is a reasonable proposition because it can serve as the stepping stone to other destinations in the solar system. The low gravity makes it more attractive to mine and build things on the Moon rather than having to uplift everything from Earth.
[1] http://www.space.com/7335-water-moon-suddenly-attractive-des...