In chapter 6 Napoleon has pretty much set himself in charge of the farm without taking any ideas from anyone else. He thinks he is much better then everyone but they don’t want to speak up for fear of getting expelled like Snowball. To him even though he knows that Snowball probably didn’t knock down the windmill, once he gets some sort of idea he won’t deny it because he might not want the animals undermining his authority. Also he knows that if the animals find out that he didnt really know that Snowball really knocked over the windmill then they will probably want to run away and also find where Snowball went off to.