Robots are so much easier. They run on pure energy. Humans run on energy that has to be transformed inefficiently multiple times.
Robots are gay less susceptible to cosmic radiation. The cities portrayed on the SpaceX website are not radiation proof. The ISS is not exposed to the full force of cosmic radiation.
Robots don't care about low gravity. We have no idea what the effects of long term low gravity are on a population.
You can send an email to book a place on a mission to Mars on the SpaceX website.
Sure, I agree with all of that. For most purposes, I think robotic missions are preferable to manned missions. There is one class of mission that I think requires humans, though, and that's "human exploration". If the point is to send humans to Mars, then you need to send humans. Why would you make that your goal? That's a different discussion*, but given that many people see it as a goal in its own right, it's not a goal that can be achieved with robotic missions.
*One example, is that there are people who want to go to Mars. If they want to go to Mars, that's not a desire that can be sated by any achievement of robots. Some other people just want to see other humans on Mars. You may not see either of these desires as valuable, but that's a discussion about other people's values.