My anthropology teacher used to tell us horror stories about missionaries in South America; of them being tortured & about their own torture, which resembled a story like bellow.
http://www.webindia123.com/news/showdetails.asp?id=60965&n_date=20050116&cat=India
It is not a Christian missionary problem per se, or a religious problem altogether. For example, great powers of today help those who befriend them or where they have self interest while the others get a lip service.