We are a long ways away from having robots that are advanced and flexible enough to replace people.
Well trained, educed people die every year in the thousands from completely unnecessary activities like wing suit jumping. Many millions if you include things like smoking and drinking.
I don't see anything wrong with a few astronauts willingly risking their lives on new frontiers.
And I'm sure this will happen once we have the capability. I think the primary reason why we haven't sent anyone to Mars is the lack of public interest and funding. We don't even have the rockets to launch any considerable payloads to Mars, without incurring insane cost.
Starship (the new rocket from SpaceX) makes me optimistic that things might actually happen in the next 1-2 decades.
http://www.homepages.ucl.ac.uk/~ucfbiac/Human_efficiency_pap...
So before any scientific equipment you've got literal tons of life support to get to Mars. For robotic probes they can be mostly scientific instruments. They also aren't really limited by consumables like astronauts.
It's not like astronauts wouldn't be cool or useful but for the same cost as one manned mission we can spam Mars with robotic probes. There's also the added benefit of an unexpected lithobraking not leading to some flag draped coffins and a total halt to the program for years.
Or we need to retool and try to get robots to mine the asteroids for us-cus money.
I'm not against manned spaceflight at all but I think it's important to recognize it is very expensive per quanta of scientific data. In a world where money for pure science can be hard to come by it's often better to get more science bang for your space bucks.
Clearly, if we send people on Mars we should make sure they are not just well trained and educated.
This seems highly unlikely at first glance, given the fact that Curiosity has been able to explore 25km and has been performing experiments and observations for 8 years and counting. A human on an exploratory Mars mission would not be able to venture any significant distance from the landing site (unless you also send a vehicle down), and they would definitely not survive for 8 years of soil-level observations.