It's because of Clarke's book!
And 50 years after Apollo 11!
But why not 2018? That's my zip code!

BTW, there are discussions about the Delta V being more favorable for Mars than for the Moon.
That's true for unmanned missions!

But manned missions are a different matter!

For instance: a manned moon mission can involve astronauts in a tiny lightweight capsule going into orbit around the Moon and a lunar lander that is open, where the spacesuited astronauts go from Lunar orbit to the ground, in 15 minutes, in an unpressurized environment. Sure there is fuel needed for powered descent, but the mass to take down is minimal.
But if a manned Mars bound vehicle gets entirely to its surface, this is going to be a much much more massive vehicle (the trip is 60 times longer) which will anyway require some amount of fuel to slow down to the surface (and definitely no airbags).
I wouldn't be surprised if the amount of fuel needed after parachute deploy wouldn't exceed what a lunar lander would need (smaller gravity well on the Moon too).
Anyway, the mass factor is what matters and a trip lasting 60 times is definitely going to require more mass for all kinds of cumulative reasons.

Raoul