"Can't we just have a humanoid robot go and turn the screws for us?"

That would indeed be the best solution, if we can build such robots. Notoriously, computers are much better at "thinking" (or simulating thereof) than at folding laundry.

"it's now human lives on the line if things go wrong."

That is quite normal in many professions. Programmers are usually somewhat sheltered, so the very idea of risking your life on a job is shocking to them. But I grew up in a mining town and, well, some people will take that bargain for money. Some people even like the bit of a thrill.