Maybe because Witchcraft and Paganism comes from Europe while a lot of Asian people come from... you guessed it, Asia.
If you examine things like Taoism, Traditional Chinese Medicine, Shintoism, you'll find a lot of similarities.
Oh, and karma, chakras, reincarnation, etc. which are all celebrated these days as part of witchcraft, new age paganism and other such traditions? Those actually come from the Asian subcontinent of India. They have very, very little to do with the original traditions of witchcraft and paganism.
Educate yourself before stereotyping an entire race.