There is absolutely no good reason for humans (except saving priv..I mean Matt Damon) to go to Mars. Send robots, take pictures, frame them. Ah, we already do those.
For what? Humankind ruining the Universe? The Moon is much closer, simpler, cheaper. If the Earth get hit by another asteroid the colony on Mars would die off too, because they can not be selfsustained. There is a simple Musk rule: If Elon says something the opposite of it is true. There is no Departure from Mars, by the way. It is a one way dream.