Railways usability

On Dutch trainstations, the timetables show a line with train stations at the top, and a table of times, platforms and further info (such as the type of train) under it.
Yesterday, I came across the following puzzling timetable.
First, all stations on the line were marked "IC".
A text under it said, 'Warning! Intercity trains only stop on stations marked "IC".'
In the table under it, every single train had the word 'Intercity' next to it.
So basically, all trains always stop at all stops. I wonder why they had to say this in such a roundabout way.