There's some hyperbole in what Bezmenov claims will be the consequences, but psyops and information warfare are very much real, and have been in use for decades. If he defected from the USSR and worked as a propagandist, he would be very familiar with what these tools are capable of. And if you take a look at the current state of many Western countries, it aligns well with the effects of psyops. Whether it was done by internal or external forces doesn't matter much, but it would be naive to think enemies of the West aren't engaging in it, just as the West is[1].
There's a very interesting read on the USMC University website that covers political warfare (which this would arguably fall into). Its freely available.
[1]: https://www.washingtontimes.com/news/2022/sep/19/us-governme...