It means that you raise an entire generation with this insane liberal agenda from birth, then after 15 years once they begin to have a voice, they can no longer come to rational conclusions despite having all of the information in their faces. They will no longer be patriotic. They will no longer want to defend themselves. And more importantly they will no longer want to protect America.
I'm slightly confused about the meaning
It's a quote from Yuri Bezmenov. Watch this video to start.
The Left-wing Plot to Cause a Race War in America https://www.youtube.com/watch?v=j5z24KKd_BQ
Don't just believe him. Do your own research using his content as a reference. Get as shocked as you can handle.
It means that you raise an entire generation with this insane liberal agenda from birth, then after 15 years once they begin to have a voice, they can no longer come to rational conclusions despite having all of the information in their faces. They will no longer be patriotic. They will no longer want to defend themselves. And more importantly they will no longer want to protect America.