Back in 1987 KGB Defector Yuri Bezmenov explained how Ideological Subversion works.
Around the 5 minute mark he explains that "most of this has been done to Americans by Americans because of a lack of moral standards."
In around the 2:15 mark he speaks of at least 3 generations (back then) of American students having been indoctrinated with Marxist-Leninist ideas without any counterbalance. And he says, "The results are clear, the Americans educated in the 1960's these drop outs and half-baked intellectuals now occupy most of the positions of power within the U.S. government, Civil Service, Business, Mass Media and the educational system." He called this prolonged process, "Demoralization."
Interestingly enough around the 3:45 mark he talks about these people (our social justice warriors and leftist protesters) being the first and primary group marked for death under the kind of government they push for. As he replied to a question on that he replied, "Most of them, yes,simply because the psychological shock that they will experience when they see in future the beautiful society they envision will actually be like in practice, all those dedicated to equality and social justice will be appalled...they will revolt. They will be frustrated, unhappy people and no Marxist-Leninist regime will tolerate these kinds of people. There will be no room for such people in future Marxist-Leninist America. Unlike today when Daniel Ellsburg and Jane Fonda can get fame by criticizing your Pentagon, in future they will be squashed like cockroaches."
It's a very interesting interview.