The core problem is that it defines roles and then says that if you don't do all of it, as stated, then you are not doing it.

Plus, they have changed it so, so, so many times, in massive ways, indicating that they don't know what they are doing. There are far, far better sources for learning about effective leadership, or how people collaborate well. The Scrum practices, which keep changing, are over-simplifications of complex topics. You can't distill this to a process defined by roles and events. In fact, for each of those, there are better ways. Scrum is really a set of anti-patterns for how _not_ to achieve the things that Scrum says it is helping to achieve.