Enforced group mentality is about as common under capitalism as it is under socialism...but it's much more subtle under capitalism. It is achieved mainly by marketing, advertising, and mass media. People go out and buy what they are told to buy by the mass marketers. They do what they are told to do. They vote for whom they are told to vote for. He who controls the media effectively controls the actions and thoughts of most of the people most of the time.

I call that enforced group mentality...achieved through clever and incessant marketing. Remember Vance Packard's "The Hidden Persuaders"?

Big Capitalist Brother is in charge most of the time, Amos...over most of the people.