Historically, there are three important sides, and roles, for each project. Product management - takes care what the customer wants to have build. Project management - takes care of what is delivered is on schedule and that there is enough material/personnel to build it. Architect/engineering lead - takes care of whether the thing is technically feasible, what technologies are used and what technical trade-offs are made.
And there was a vast literature and discussion about how these three sides affect the result of the project, and how to solve these problems.
Unfortunately, Scrum, renaming everything, acts as if the history of project management doesn't exist. And if you forget history, how are you supposed to learn from it? That makes it easy to sell snake-oil. I frequently hear, for instance, that scrum master is not a project manager, despite him having some responsibilities in this area.
And as the blog post also expounds, there is no recognition for these three different sides of each project in Scrum (ironically, there is some recognition of that in Scrum derivatives such as Scaled Agile Framework, for instance, modulo nonsensical renaming of the roles).