It's not like they will be walking around in shorts and t-shirts.
Frankly, I think there is some good reasons for a mars base. It's a shorter distance to the asteroid belt where mining could become a profitable idea.
At the very least, aiming for mars colonization would give us something to strive for and develop technology for. The stuff that came out of the moon program is still incredible today. We need big ideas. Somehow back in the 60s and 70s, big stuff managed to get built. We should return to that style of doing things. In my city, Montreal, they can't even replace a damn interchange built in the 60s which is failing apart. One project, compared to about 5 similar scale projects built back then. Instead we get some odd trash disposal system (read wired this month).
It's not so much that it's a shorter <i>distance</i> to the Belt as that the gravity well of Mars is so much shallower than Earth's - making Mars a cheap place to grow food for distribution in the Belt. The surface of Mars is roughly the size of Earth's land area, so there's lots of room for farming. OK, not so many volatiles - but put up some greenhouses and you're good to go.
Cold might be a blessing in disguise. Pretty much any off Earth colony is going to require extensive life support. All that machinery will need a place to dump it's excess heat.
