Bit of a straw man - nobody said anything about pushing for perfection at home, just "we can do better than this".

Also - "right there for the taking" gets to the heart of my objection as it is nowhere near true. Space is vast and delta-v is expensive - even if we get past the problem of deadly radiation outside the ionosphere, we are incredibly far from being able to make space travel anything other than an enormous sink for money and resources.

Maybe I'm optimistic, but these are just problems to be solved. Space exploration is a big risk / big reward investment. Yes it would require a comparatively huge investment to mine an asteroid vs. open a pit mine in Brazil but "mining" an asteroid likely means carving off hunks of solid metal for transit back to the Earth's surface rather than processing megatons of rock by blasting, trucking, and smelting. Like many things about space, it boggles the mind that a single asteroid mining mission could produce more platinum group metals than have ever been mined on Earth throughout human history. How does the total amount of money and resources spent on mining those metals on Earth stack up against the cost of a single successful asteroid mining operation?

I think this argument extends to colonization efforts as well. What is the economic and cultural benefit of founding a new nation? It's not something that we are familiar with at this point in history so we are relatively blind to it. We just take it for granted that the nations in which we live have always been there since they have always been there for us. I have no doubt that once we begin colonizing Mars or the Moon or even just Earth orbit it will have as great of an impact as the colonization of the New World.