All software in existence is engineered. To write software is by definition engineering. It is something that is devised by someone. Liability has nothing to do with the term engineer or the act of engineering, it’s not a part of the definition or history of the word.

What I feel like you’re referring to is a “Professional engineering license” as it’s known in the states, which is something entirely unrelated to the act of engineering as a whole. That’s a licensure invented long after the fall of the Roman Empire and it’s that licensure, not the word “engineer” which incurs the liability you’re talking about.

You’re confused because like I said, the organization(s) that are responsible for that licensure picked a bad term for it, because it’s too similar to the word “Engineer” which doesn’t inherently have anything to do with it. If they had coined a more concise, specific term related to what they do, like Surgeon, they wouldn’t have this problem.