Rinpoche discusses how Buddhism is adapted in every new culture where it takes root, whether that is Tibet, China, Japan, or America. DPR was raised in the household of HH the 16th Karmapa, completed 3 year retreat, finished first in his class at shedra, and received a completely traditional Tibetan Buddhist training. However, he also visited the US in the 1980's as a young teen, returned to attend Columbia University, then became a US citizen in the 1990's. He is in somewhat of a unique position (for a Tibetan lama) in that he has been able to not only closely observe both cultures for an extended period of time, but to fully embrace both, and he now offers his insights into what a uniquely American Buddhism may look like. The process is only beginning; it remains to be seen what will develop, but Rinpoche is convinced that the cultural forms that were relevant in Tibet are distinct from the Tibetan teachings on Dharma, and that many (not all!) traditional cultural accretions ultimately will hinder deep understanding of how to live the Buddha's teachings right here, right now, in 2010 in America.
Rinpoche is pushing the limits here, and apparently pushing some buttons as well. However, his point, so far as I have read in "Rebel Buddha," is to challenge us to explore and question without fear. Our American cup may look very different from a Tibetan cup; is the water pure?