That is just a historical fact. For China to insist that the Dalai Lama say it ain't so is rubbish. Let's assume the Dalai Lama says what China wants him to say. Will that change history? Not at all. Tibet was an independent country for most of history. Nepali history books are full of references to Tibet. (Tibetan Empire)
What the Dalai Lama can say and has been saying is that he is not seeking independence for Tibet. He just wants to be able to visit. That is a fair, simple thing to ask for. Why can't a Tibetan visit Tibet?