What was one of the main reasons the portuguese and spanish failed at enslaving native people of the new world

The main reason was that they were extremely violent and tried to impose their will. Anyone who opposed would get killed so there were many uprisings and since they did not know the land, the natives would often win through guerilla warfare and traps throughout the woods. Unlike them, French and British cooperated with the natives and won them over with politics and wealth.

Where are the statements, only the paragraph is here