I don't understand why the human cost of space travel is always weighted so heavily. All exploration costs lives. How many died conquering America? Exploring

I don't understand why the human cost of space travel is always weighted so heavily. All exploration costs lives. How many died conquering America? Exploring the poles? The Everest? To this day people die in the Everest. It's their choice to risk their lives in such a way. Yet I don't hear people saying "don't go there". Space is riskier, but also has more rewards.