Yup - I believe propaganda as such are a social license for acceptable politics that aligns along with their material conditons - USAmericans are generally correct that historically aligining with imperialism benefits them materially and their politics reflect that. It is partly that labour aristocratic bribe that challenges the notion of workerism as an effective anti-imperialist strategy.
So when one is asking who has revolutionary potential (similar to the beginning of the 20th century where it was discovered peasants in addition to the proleteriat had potential in Russia and China), in the 21st century we are asking which groups material conditions within the US will benefit from the fall of US imperialism. That is what requires a deep statistical study and the PSL does not appear to give the impression that they have done so.
The article is essentially a materialist challenege to the idealist notion of brainwashing. I'm glad you have read it and you can see the challenges ahead