Population control is actually a term I borrowed from the counterinsurgency literature of the Kennedy years. The main targets at the time were Southeast Asia and Latin America, where there was an awful lot of popular ferment. They recognized that the population was supporting popular forces that were calling for all kinds of social change that the United States simply could not tolerate. And you could control people in a number of ways. One way was just by terror and violence, napalm bombing and so on, but they also worked on developing other kinds of population-control measures to keep people subjugated, ranging from propaganda to concentration camps.
Propaganda is much more effective when it is combined with terror.
You have the same problem domestically, where the public is constantly getting out of control. You have to carry out measures to insure that they remain passive and apathetic and obedient, and don't interfere with privilege or power. It's a major theme of modern democracy. As the mechanisms of democracy expand, like enfranchisement and growth, the need to control people by other means increases. So the growth of corporate propaganda in the United States more or less parallels the growth of democracy, for quite straightforward reasons.