It seems easier because Mars proponents often focus on the technological challenges (which are indeed great, if not insurmountable), while ignoring the human challenges. The challenges from human nature are going to exist on Mars just as much as they do on Earth; things like warfare don't suddenly stop existing just by shifting people to Mars. People act like Mars would be a place to keep people safe from nuclear war, but destroying a Mars colony from Earth is trivial compared to creating one.
If one looks at the history of colonies (attempts to colonize the new world, for instance), we see that they often fall apart socially even in situations where they're in a place with much more resources than they had back home. Humans aren't dwarf fortress type automatons that can simply be handed whatever necessary job is needed and mindlessly go about their day for the rest of their lives.
No one has been able to manufacture a functioning mini-society, and every attempt has ended in spectacular failure. It seems crazy to think things will suddenly work if we drop the people in a place devoid of almost all resources and entirely hostile to life from Earth.
How can you bring humans to Mars without also bringing human nature, i.e., human flaws? We'll wreck Mars quicker than Earth, because Mars is already a wreck.
It's not a question of starting or stopping; whether we start or stop seems irrelevant to me. The point is that humanity has been "coddled" by the Earth, because we were born and evolved here, but we won't be coddled by Mars, and thus the Mars project is doomed to failure, since we're already failing on Earth, in a vastly more favorable environment.
What's the point of a "backup plan" when the primary plan isn't even working?
Humans will still be the ones colonizing Mars, the same humans who would theoretically make Earth uninhabitable. If we humans can't stop destroying Earth, we have no chance in making a Mars colony successful.
If one looks at the history of colonies (attempts to colonize the new world, for instance), we see that they often fall apart socially even in situations where they're in a place with much more resources than they had back home. Humans aren't dwarf fortress type automatons that can simply be handed whatever necessary job is needed and mindlessly go about their day for the rest of their lives.
No one has been able to manufacture a functioning mini-society, and every attempt has ended in spectacular failure. It seems crazy to think things will suddenly work if we drop the people in a place devoid of almost all resources and entirely hostile to life from Earth.