I think the person you're responding to had a solid point, but he derailed it with his own examples. It's not about "throwing out the value of human life" but appreciating that risk is something that, in many endeavors, is going to remain relatively high even if you make every effort to minimize it.

When we went to the Moon, the obituary for the astronauts was written before they even took off. And the astronauts themselves felt they had somewhere from a 50% to 70% chance of success. Everybody was well aware of the extreme risks, but they still voluntarily participated, because they felt the achievement was worth the risk. And indeed those brave men inspired an entire generation to science and achieved what many believe was still the greatest achievement in humanity's entire history.

The first missions to Mars will always be high risk, because the fundamental issue is that you're always going to be doing a bunch of things that no other human ever has. There's just so many unknown unknowns there that we're going end up getting surprised by something. So all we can do is make sure we have highly capable people and try to prepare as well as we can. But in the end, even when you work to minimize risk as much as you possibly can, that mission will always qualify as 'risky.'