That's not what he meant. He just meant that the movies need to be able to function narratively as their own self-contained entity. After all, quite a lot of the people who see the movies are not going to be viewers of the shows. It's a given that if a franchise has works in different media, they won't have the same audience; indeed, that's the whole reason for expanding into different media, so that you can draw in multiple audiences.
So any work in a multimedia franchise has to fulfill two goals. It has to work both as a standalone tale in its own right
and as a part of a larger whole. And the former is usually the higher priority, particularly for the dominant thread with the largest audience, which in this case is the movies. So the goal is to keep the films and the shows consistent with each other without depending on each other.
So yes, in the grand scheme of things, the movies and AoS are in the same universe. But the movies also need to be able to function as their own independent whole, to shape their own path rather than being shaped by events in the TV shows or the shorts or the tie-in comics. That way, the people who see only the movies and nothing else will get a complete and consistent story, one in which Coulson's death has a lasting meaning. But those people who watch both the movies and the shows will get a different, wider perpsective on events, in which Coulson's death was just part of his ongoing story.
So he wasn't saying that AoS isn't part of the same "reality." He was just saying that it needs to be a distinct thing
narratively. The interconnections between MCU works are a bonus, but the individual needs of each story predominate. That's why you didn't see the Avengers coming down to fight the fires in Hell's Kitchen in
Daredevil. Theoretically the same world, but narratively independent storylines.