People have other reasons of going. You don't colonize during the asteroid event, you colonize long before. You won't have people fighting to go to save themsel

People have other reasons of going. You don't colonize during the asteroid event, you colonize long before. You won't have people fighting to go to save themselves, you'll have them wanting to go for various reasons, legacy, reputation, isolation, etc. That being said, I don't agree with your premise that you can't be a healthy person and care about the human race. You haven't added enough to support that claim.