The control of American culture comes from the government, and those who have influence on our everyday lives. For example, the government imposes dress codes, bans books, etc. So that eventually one day these things will come into normal practice without second thinking their choice, as if these bans on laws on ridiculous things were never there. With the dress code for instance, they intend to make everyone not wear certain types of clothing.
Since students can’t wear them, demand for them goes down and eventually is erased from existence, as habits are built on the next generation to not wear these types of clothing ever again. This goes for anything else that is trying to alter the way we think or how we want to do things so that they will have more and more control over culture, and us, according to an unknown group controlling it all.