The interesting thing about propaganda is that it is often not the Contant of the message itself that determines whether the message is propaganda, but rather the context in which the message occurs.

For example, if government A which in recent memory has killed 1 million people says, “oh my God, government B just killed 1000 people they are pure evil!“ I would argue they are engaging in propaganda because intrinsically they are asking you to make a moral judgment of government, B’s behavior absent the critical context of their own behavior.

Granted, this is over-simplifying it a bit, but I think the principle is pretty easily and intuitively understood and applied. If governments A and B are engaged in some sort of a geo-strategic conflict, then their behavior relative to one another, becomes even more critical.