What people call waterfall is really called REQUIREMENTS, and they happen, no matter the ideology or discipline.
For example, I’m building a new home, I start with the foundations, then the walls and finally the ceiling and it is exactly a waterfall. Separating the project in small parts will not do any magic.

I write an article about it
But even more
Agile is about being adaptive rather than predictive.
– Martin Fowler
That is an irresponsible way of planning a project. Martin Fowler could be a good programmer but it’s a lousy project planner.
When we start a project, someone must be in charge of planning the project. With Agile is simple, the planning says “Let’s the team decides and later I will change the rules at whim!”. Of course, it will not work. Change happens but we can’t be adapted to changes. It is the same to have a PLAN-B and say “Sooner or later, we will use the PLAN-B” (then why not simply started with the PLAN-B?).