The issue of Mars colonisation (or space colonisation in general, if we don't want to get into the planet/habitat debate between space advocates) is surprisingly one of the key dividing lines in present day politics.
You can reliably predict someones opinion on it by which party they vote for, by how they feel about Elon Musk as a person, or by their level of optimism/pessimism about technology. There is almost total correlation on believing it is a good/bad idea from a technical perspective and thinking it is desirable/undesirable from a political perspective. Everyone seems to be quite sure that the laws of physics vindicate their opinions on this matter.
Its not surprise I'm in the "let's go" faction. But I am increasingly of the view that even beyond the issue of Mars, that faction must win, or else Earth as well will be sunk into the mire of degrowth, envy politics, and misery.