Is this really how American missionaries treated Pacific islanders?

I don't know about the missionaries, but Margaret Mead's work, "Coming of Age in Samoa," has been revealed to have serious flaws. In short, she was taken in and sold a fictional version of Samoan morality by two teenage Samoan girls who thought they had a good joke on her. Ms. Mead swallowed it whole and wrote her book on the girls stories without researching more deeply.

The best diplomat I know is a fully charged phaser bank.

Yes, missionaries often punished and even killed those who would not conform to Christianity. Not to mention the destruction of culture and history by missionaries. Persistent unbelievers, those who refused to be converted, were executed. Singing was banned (except for hymns) and all forms of adornment, flowers or tattoo were disallowed. Of course, surfing and dancing were not permitted as well. The punishment for breaking any of these rules included, among others, being sentenced to hard labor.

Missionaries would introduce the local chief to alcohol, made him addicted to alcohol, convert him to Christianity and then leave it to the chief to convert the locals. After converting the majority the minority that refused to convert were persecuted and sometimes executed.

One early twentieth century Methodist missionary in Umtali, Zimbabwe, wrote of the people he had set out to evangelize: "Heathen and naked as new born babies, and as ignorant as beetles." The missionaries became part of the oppressive colonial forces in Africa.

The worst, without a doubt has to be in South America where the missionaries are at their most destructive. During the conquest of the "New World", beginning in the 15th century, Catholic priests and friars, accompanied the invading armies of Spain and Portugal. All kinds of coercive methods were used to subjugate and evangelize the Indians. The Indians were exploited, enslaved and made to work for the settlers in return for protection and religious instructions. A total of up to 15 million Indians were reported to have died due to such brutality.

In response to the Mead controversy it's important to look at the source, Derek Freeman. A man who after a nervous breakdown focused on testimony from some of Mead's subjects some 30 or 40 years after Mead did her work. Freeman's only mainstream work was trying to discredit Mead who was one of the more important anthropologists of the 20th century. Freeman, banned in Borneo, went on to study psychoanalysis for two years. In researching Mead and Freeman during college I find Freeman to be a very unstable individual. As with any online reading I encourage you to do your own research into the missionary system and anthropology. In the end you'll are only left with one conclusion. Christianity destroyed history and culture in almost every place it touched. Ain't it wonderful?