What is the propaganda in Squealer's speech?
Propaganda is information that a person or group uses to promote its ideology and ideas. Propaganda tends to be biased and/or based upon distortions of the truth. Napoleon uses Squealer to change the commandments and spread lies about Snowball.
At the end of Chapter 5, Squealer is giving his justification for some of Napoleon's new policies. He concludes by saying that they are better off under Napoleon than Snowball, the traitor. In truth, Snowball was loyal to the cause of Animalism and certainly was not a traitor. Napoleon and Squealer are using their propaganda to tarnish Snowball's reputation.
When the animals counter this by saying that Snowball fought bravely at the Battle of the Cowshed, Squealer replies, "And as to the Battle of the Cowshed, I believe the time will come when we shall ﬁnd that Snowball’s part in it was much exaggerated." Squealer attempts to downplay Snowball's heroism.
Squealer makes propaganda speeches throughout the novel. Every time Napoleon changes the commandments, Squealer is there to trick the animals into believing that no changes have been made. Every time Napoleon hoards more of the food (i.e., hens' eggs), Squealer is there with a biased justification.
In Chapter 7, Squealer continues the false accusations about Snowball:
Snowball has sold himself to Frederick of Pinchﬁeld Farm, who is even now plotting to attack us and take our farm away from us! Snowball is to act as his guide when the attack begins. But there is worse than that. We had thought that Snowball’s rebellion was caused simply by his vanity and ambition. But we were wrong, comrades. Do you know what the real reason was? Snowball was in league with Jones from the very start! He was Jones’s secret agent all the time.