Final answer:
The Pilgrims were called "Separatists" because they wanted a complete separation from the Church of England.
Step-by-step explanation:
The Pilgrims were called "Separatists" because they insisted on a complete separation from the Church of England. They were dissatisfied with the Church of England and believed that it could not be reformed enough to meet their religious beliefs. They wanted to establish a separate and independent congregation where they could worship according to their own ideals.