I think the label of "irresponsible" fits with respect to calls for human landings on Mars at this time. We simply don't have enough of a track record with the unmanned craft to justify a manned mission at this time.
During the Apollo program, right up to the events that cost the lives of Astronauts Grissom, White and Chaffee, there was a throw-caution-to-the-wind mindset that was later dubbed "Go Fever." It cost the lives of three people in 1967. The disease made a comeback in the '80s and claimed seven lives on January 28, 1986.
Judging from the calls to send people to Mars at this time, I'd say the disease is making the rounds again, albeit in the public sector only.
Considering that we're approaching the 1-year anniversary of the Columbia tragedy, I'd rather not see people once again fall under the impression that space flight is somehow "easy."