Answer:
The central idea of this passage is that the pigs, specifically Snowball and Napoleon, along with the full agreement of all the other pigs, are exploiting their authority and becoming corrupt. They are taking advantage of the farm's resources, such as the milk and windfall apples, for their own benefit without sharing them equally with the other animals. This demonstrates the pigs' increasing greed and abuse of power, leading to inequality and corruption on the farm.