But you'll go on believing it anyway.
I just came across Prisoners of Shangri-La: Tibetan Buddhism and the West by Donald Lopez, Jr, which was published by the University of Chicago Press in 1998. This is not the first book I've read about how Western intellectuals got aspects of Asian culture wrong. It is, however, a decisive take down, with detailed notes and references, of the basic image that Westerners have of Tibetan Buddhism. Including me. Ouch.
Lopez traces the historical and ideological record of the term lamaism, a derogatory label for Tibetan Buddhism, and shows how Western labels came to be used even by Tibetans. He shows how the West came by its translations of the Book of the Dead, which turns out (surprise!) to involve the exploitation of a native culture bearer to serve the ideological agenda of Westerners.
Lopez also reviews the fascinating case of a British ne'er-do-well who pulled off a publishing coup in which he described his life as an especially gifted Tibetan sage. He goes on to excavate the philological history of the famous mantra "Om Mani Padme Hum" and in doing so once again proves the point that Westerners were more than happy to make up definitions when language or cultural barriers threatened Western thought boundaries.
I feel so lucky to live at a time when, even being poor, I have a collection of some of the world's best English translations of Chinese classics and Buddhist literature on my shelf. These were translations that simply were not available until 20 or 30 years ago. In that regard, we can't blame all these progenitors for seeing things their own way. We're just the same - and all better, I think, for the continuing efforts of the translators.