There’s no great point to having 20k in Antarctica. Becoming a multiplanet species does have a great long term point, but it’s more of a thousand year vision than a five year vision. Many of Mars’ shortcomings can be improved upon but they’re slow and take a lot of scale. Open bodies of water and a breathable atmosphere are entirely possible and more of an challenge of developing the scale than solving a scientific obstacle.

If you don’t want to do it, don’t do it, but don’t stand in the way of people who want to try.