Space travel to Mars is not too dangerous to attempt. When one makes a determination of the risk of any significant endeavour it must be weighed against the gains. Exploration and colonization is a human imperative we should not ignore. The human race needs heroes, adventurers, and explorers this alone is reason enough to brave the journey.
The risk of any voyage to Mars must be carefully weighed against the possible rewards. Any such mission to Mars would bring huge scientific discoveries. We could learn so much about our own planet by being able to compare it to another planet as close to earth like as Mars. Just the comparison of weather and atmosphere could help climatologists gain a better understanding of our own climate. The geology of Mars would give scientists insight into our own Earth's formation as well as insights into the formation of the galaxy. The impact of the possible discovery of life either existing or fossilized on Mars would be earth shattering to biological sciences. The journey to Mars would require a great scientific effort in order to be possible humans would reap the benefits of this just as we currently do with the existing space programs.
Exploration and colonization are important to the future of our race. The diffusion of humans throughout the world helped protect the whole population from being at risk for disease. The future colonization of other places in our solar system will help insure the future of our race in the case of a global catastrophe on earth.
The human race needs heroes, new frontiers, and new vistas to see. If you could for a moment imagine the impact to the human race of our first view of the earth rising as seen from the surface of the moon. The social impact of having fellow humans on the red planet will be similar. Humans need to feel like there is still a frontier they haven't seen a place that still needs to be explored. In a world where Arctic cruises are a yearly occurrence we need to expand our horizons, our vision. When the world becomes so small humans need to be reminded that they are not the centre of the universe a voyage to Mars would give humanity a reason to reflect on how vast the universe is and how much we have left to find and learn.
Travel to Mars is not too dangerous it is a human imperative. The question then becomes not if we will do it but when. The cost and danger is an illusion when compared to the benefits to mankind. No, the danger is not the trip to Mars but the possibility that we would put it off.