I don't think the argument would be that the opinions that people form, or want to form, always come from a conscious understanding of imperialism. The author would likely say that Westerners want to believe, and do believe, the rest of the world is bad, dangerous, unfree, undemocratic, totalitarian, etc. to make them better about their own lives - even if, or because they are, facing difficulties themselves.

The article mentions China and the supposed genocide of Uyghurs in Xinjiang as an example. The phrase may as well be gibberish to Westerners. They don't know, nor want to know, anything about the topic.

You are right, they aren't doing any critical thinking. They are simply repeating nonsensical lines and absurdities, and they don't want to think about it.

They don't understand imperialism on a conscious level. But they want to believe that even if they can't pay their bills, and their own life in the West has its hardships, and their state could be doing more, that at least other places are worse. And they want to feel superior to the rest of the world, so they believe any atrocity propaganda they stumble across to fuel their coping mechanism. But it doesn't require an understanding of imperialism on their part. If they think about it at all, I'd guess they would attribute the superiority of the West to white supremacy, "democratic values", etc.