Smart people have strong views on human space flight. In my mind, human space flight isn’t a football for arguments over public verse private. How missions are funded is less important than the fact that they are funded. Space flight will always be a high-risk activity. Those risks will sometimes be borne by the public sector and sometimes by the private sector.
Saying that all we need is robotics in space is to overstate the case for robotics. No doubt, robotics will play a fundamental part in exploration. It’s one component in a bigger picture. Humans need to go to space. That’s a rather a didactic statement. It needs to be challenged. So, my answer has several parts, and here they are:
Firstly, it’s not that we have a choice, given the nature humans have demonstrated over the last million years. Discontent with staying in one place, we are constantly on the move. We’ve inhabited every part of the globe. Even the most inhospitable parts. It’s extremely unlikely we will counter that instinct to travel, to go, and to see for ourselves. First-hand.
Secondly, every robotic mission has limitations based on the design of the machines we send into space. A designer must use the knowledge of their time to anticipate what may be needed, often a decade from the first moment they sat at their computer. The adaptive capability of humans is unmatched. However, machines advance, it will be unmatched for tens of decades ahead.
Thirdly, our lives are full of stories of imaginary flights. From Leonardo da Vinci vivid creativity to the practical achievements of the Wright brothers. Imagination spurred on inventors to bring to life ways in which humans could take to the air. The same applies to space flight. Flash Gordan is a comic book character. We know that Star Trek is a fiction. The film Gravity stressed the dangers of space. None of this detracts from an imbedded predisposition we have for space-based adventures.
Fourthly, when faced with the new it’s not always clear what to do. However, if unprecedented situations arise, we humans rise to the occasion. The inventive capacity of people is unique. When the machinery around us fails we come up with answers. We work out a way to get over the problems. Being able to rapidly fix things matters in space.
Fifthly, our species is successful, in part, is because we face risks. It could be said that existence requires us to face risk, but we do it anyway. Our enjoyment of dangerous sports is one indicator. People train to face perils and are thrilled to overcoming challenging circumstances. Collectively we delight in their achievements. Why go to space? – Because it’s there.
It’s more than evident that from the perspective we have in the here and now, we can only see so far ahead. A few will see further. What seems obvious to a highly educated commentator on human space flight may be rendered null and void at a stoke come the next discovery.
NOTE 1: On the third point, I found a quote from Orville Wright. “No flying machine will ever fly from New York to Paris. That seems to me to be impossible. What limits flight is the motor.” So, even with his inventiveness and imagination it only went so far. [Early Flight – From Balloons to Biplanes].
NOTE 2: On the fourth point, the experience of my early career working on ground test equipment for communications satellites comes into play. Extensive testing is needed on any space borne systems. As I remember it being said – we don’t make ladders that high.
 Why climb a mountain? British climber George Mallory gave a famous response in a New York Times interview in 1923: “Because it’s there.”