C / C++

Computer programmers create software. Systems are constructed by software engineers. As far as I can tell, that's the main difference. It's one thing to create a software that really does anything. It's another thing entirely to design a software that works and can interact with a wide variety of other programs. And it's an entirely different thing to write a programme that can work with many other programs, run many instances of these programs simultaneously so you can handle massive transaction volumes, and then figure out how to keep the whole thing running when one or more of the programs is failing, especially since a failure in one programme usually results in the effects of the failure cascading through. Scalability, error detection and correction, fault tolerance, analysis of failure, monitoring, tuning, alerting, privacy protection, and the management of scarce resources are all part of software engineering. Most programmers won't encounter issues like that. And that's how people become software engineers in the first place: because they have to.