Antarctica is practically a tropical paradise when compared to space as well, which is something I always like to mention whenever someone makes a positive assertion about the viability of space colonization.
People take for granted that an inhospitable environment here on Earth (whether it be Antarctica, the top of Mount Everest, the North Pole, the Atacama Desert, Death Valley; take your pick) would be a highly undesirable place for people to live, yet these same people seem determined to believe that this understanding somehow doesn't apply to the rest of the Solar System, which is not only much more inhospitable than just about anywhere here on Earth (no breathable atmosphere, for a start), but is also much more expensive and impractical to get to.
The only way I could see space colonization becoming viable is if we were able to construct mega-structures such as the ones advocated by Gerard O'Neill, but I'd wager that we won't have the capability to do anything like that for centuries, if at all. Natural satellites like Mars and the Moon are dead ends for the simple reason that even if terraforming them was possible (doubtful), there's still no way of solving the problem that they lack Earth-like gravity.