Engineer started as a word meaning one who is skilled in the design, construction, or use of, surprise, engines.
The word evolved in its use to later encompass other systems that can build: civil engineering (bridges and buildings), mechanical engineering (robots and mechanical systems), and computer engineering (actual hardware).
Software is merely the latest system. Many universities grant software engineering degrees and apply principles of engineering to software.
The whole point of this article is to treat "engineering" as a reserved and hallowed word and vocation. Its name and usage must be protected at all costs lest we let just anyone call themselves an engineer.
It's an argument of arrogance and appeals to maintaining the status quo of exclusionary system. You didn't take a certain test or wear an iron ring? Sorry, you can't call yourself this one title. The title of "doctor" has similar historical exclusion, with infighting common amongst multiple professions (e.g., medical doctors not thinking dentists or PhD's are actual doctors).
Language evolves. Stop being protectionist about a certain word.