In the beginning of "The Crucible", what were a few reasons that the Puritans failed to convert the Indians?

At the beginning of "The Crucible", Miller says it was their “parochial snobbery” that prevented the Puritans from converting the Indians. Their goal was to keep the community together and to prevent any kind of disunity that might open it to destruction by material or ideological enemies. Thus, the different beliefs of the Indians were a challenge to their unity. That, combined with Puritan idea that their beliefs were superior to any others, created an attitude of superiority that would put off any people---Indian or otherwise. Thus, the Indians were known as heathens who were enemies to be destroyed, not people to be converted to belief in grace and love for one's neighbor.