I would think that she could have answered simply, "while your ideas are completely valid, we at NASA find it to be a more compelling challenge to return people

I would think that she could have answered simply, "while your ideas are completely valid, we at NASA find it to be a more compelling challenge to return people to Earth from Mars as it would provide a much better opportunity to innovate and increase our knowledge base on return mission while opening up new industries beyond simply landing Humans on Mars, but ones that span the entire Solar system".