We should never have sent humans to Antarctica. We should have relied on binoculars from ships and maybe some blimps with cameras, right? I mean, what can a human possibly accomplish that a machine can't.

Also, we didn't "send" them, the early explorers and bases were done by people who wanted to go and do research there. We have lots of people who want to go to Mars to do research or who want very much to benefit from the research humans can do better on Mars than current robots.