Marketers get the groups to approve the product and communicate that approval to its members. US is not a classless society. Social class influences many aspects of our lives. IE upper middle class Americans prefer luxury cars Mercedes. Lower class people tend to stay close to home when shopping, do not engage in much prepurchase information gathering.
Stores project definite class images.
Family, reference groups and social classes are all social influences on consumer behavior. All operate within a larger culture. Culture also determines what is acceptable with product advertising. Culture determines what people wear, eat, reside and travel. Cultural values in the US are good health, education, individualism and freedom.