To understand Animal Farm and Orwell's views, it is helpful to realize that it is allegorical and that Orwell's intention was to show how the abuse of power is relevant in most situations of governance.
Corruption often stems from an abuse of power and, in Animal Farm, Napoleon uses Squealer, the ultimate manipulator, to persuade, cajole and indoctrinate the animals into believing that the pigs have everyone's best interests at heart.
Propaganda not only confuses the animals but turns them against, for example Snowball. They are persuaded that the pigs need the milk and apples because they are "brain " workers.
They are so afraid of Jones and the other humans that they will do anything to keep him from the farm. A simple veiled threat is sufficient to make the animals accept the milk and apples scenario when they are asked rhetorically:
“.. surely there is no one among you who wants to see Jones come back?”
Equally so, they are trusting when - despite evidence to the contrary - Boxer is taken away in a van.
Squealer, "a brilliant talker," convinces them time and again, even when several commandments are changed, that they have forgotten the full extent of the commandments:
"the last two words had slipped out of the animals' memory."
The constant referral to "comrades" makes the animals feel united and they do not want to lose their group identity.
The over-simplification of the language, such as ""Four legs good, two legs bad," also consolidates the animals' position - or so they think!
Some of the themes in Animal Farm do combine as the power and corruption is strengthened by the use of propaganda. The propaganda is effective because of the animals' gullibility and Orwell's criticism of the Russian Revolution and any abusive power is evident.