The claim is that if you know 80% of the vocabulary then you learn the rest of the vocabulary through context but if it has 100% words you do not know then you do not learn any vocabularly words
He might be wrong and it might be better if you only watch shows where you know 100% of the words so you just learn the context of how the Grammar is used with vocabulary words you already know from the show and so you learn how to hear the words when they are not in writing
My experience is I have never learned much of anything by watching shows in a foreign language compared with the amount of time in traditional study
Maybe I watch for an hour and learn one or two words and any words they borrowed from other languages I already know such as mainly English
In that hour I could have memorized a lot of new words from a vocabularly list instead
But maybe the shows I watch are at too difficult a language level
