Worst Part of Animal Farm

Out of many sad events throughout the story, I personally thought that Napoleon and Squealer convincing all the farm animals to think that Snowball was an intruder, betrayer, and the one who should be killed was the worst part of the novel. After Napoleon used his privately trained dogs to chase away Snowball out of the Animal Farm, him and Squealer started to propagandize all the animals, so they think that Napoleon is always right, and Snowball was on the same side with Mr. Jones. Foolish animals believed in every single word that Squealer and Napoleon told, and later on in the novel, they were killed by Napoleon if they did not.
Snowball was a true follower of Animalism, just like Trotsky, back in the old days of Russia, but was chased away by Napoleon's dogs because he would get in the way of Napoleon's plans to gain and have the ultimate control over the farm. As soon as Snowball was chased away, the farm's process of turning into the old Manor Farm sped up. If it wasn't for Snowball's banishment, the Animal Farm could've been a powerful farm under every animals' control. However, since Napoleon got rid of Snowball, he became the new Mr. Jones, turning the peaceful Animal Farm to the old Manor Farm.