Are we wasting time and money going back to the moon? The argument 'for' says that it will be the ideal springboard for exploring further. It is an argument based on the practicalities and technology of 'now'. It is the view-point of the technocratic manager not the inspirational leader.
Going for Mars is driven by more philosophical ambitions. To go to Mars is difficult, to go to Mars is demanding, to go to Mars stretches the capability of mankind.
Big Hairy Audacious Goals are what get people going places and doing things. I'm with the Apollo astronauts on this one. The very process of 'going for Mars' will produce far more than the mere technical and commercial benefits. The Mars ambition is aspirational, it is inspiring, it is exciting.
Getting there requires collaboration. Getting above petty differences and the medieval mind-sets of the gangsters and terrorists that are so consumed with this place and this time. The people of the world need to see far into the future of possibility so that they can reject the idea that we are stuck on the Blue Marble to be forever at each others throats.
We need heroes. We need to go to Mars