I was requested to come here as it was an RFC seeing old friends it seems Anyway I don t think that quote sufficiently shows that Bon is a sect of Tibetan Buddhism or that it fits those definitions just that Bon refers to a set of beliefs that started to appear under the influence of Buddhism Isn t it generally recognized that bon believes are quite different than other Buddhist beliefs Anyway enough speculation Powers says Bon is commonly considered to be the indigenous religious tradition of Tibet a system of shamanistic and animistic practices performed by priests called shen gshen or bonpo bon po Although this is widely assumed by Buddhists historical evidence indicates that the Bon tradition only developed as a self conscious religious system under the influence of Buddhism is a very good article on the topic Maybe can find better quotes there