How much autonomy do you think doctors have? They're not in the operating room inventing new procedures. They are following careful scripts, adapted for the intricacies of one particular human body. There are times where they need to qualitatively improvise, yes, but that's generally only when something has gone horribly wrong.

Also, the Hippocratic Oath is not terribly complicated. It basically says, I will not furtively and maliciously hurt people in an abuse of my authority, and I will try to heal them when they are sick. I don't think it's a lot to ask that software engineers to agree not to create knowingly malicious software. It actually addresses exactly the problem you describe. If everyone has taken this oath, and adheres to it, there is no "someone else" to do that evil work.

Last point, there is a wide variety of software engineering work out there. Some of it may be mindless of the bigger picture of what is actually happening, but for any sufficiently advanced behavior to emerge out of a complex software product, some engineer at some level has to have some idea of the path they are going down to create or allow that behavior. And every engineer has the ultimate autonomy over how and what is created because it is our hands on the code. If you don't understand that, you don't understand the power of the profession.