I heard the argument that US used to more homogeneous ( which was reinforced by the media forcing the same values ). Now that the franchise increased with more

I heard the argument that US used to more homogeneous ( which was reinforced by the media forcing the same values ). Now that the franchise increased with more groups trying to grab a slice, the values clashed. In other words, the people were always there, but were either not visible, ignored or marginalized. I am willing to buy this argument.