Answer:
They brought many diseases such as smallpox, measles and influenza. With so many leaders and older wise people dying, the Indian nations must have lost all their sense of direction. With so many priests disappearing among these very religious cultures, people must have anguished about how to properly continue honoring the spirits of their ancestors, and how to restore their own relationships with their gods. Yes, to be causing such misery -- to even take away the powers of all the old medicines -- the gods must be very angry. What had the Indians done to deserve such punishment?