Arguably Sammy's act of rebellion in quitting his job is actually an explicit criticism of the values of his day and time. Certainly, when he quits, he cites the way that Lengel embarrassed the girls as his reason for leaving. His decision shows that he is sharply critical of the cultural norms and standards that he accepts are part of his life, and points towards the existence of a higher standard of conduct that means you shouldn't intentionally embarrass people in public in the way that Lengel has done. Note what Sammy tells us about Lengel's behaviour after he embarrasses the girls:
"Girls, I don't want to argue with you. After this come in here with your shoulders covered. It's our policy." He turns his back. That's policy for you. Policy is what the kingpins want. What the others want is juvenile delinquency.
In the story, Lengel seems to play the role of the enforcer of "policy," a term that remains unjustified and unexplained. When he speaks to the girls, he is unable to articulate the reason why they can't come in to the store in their bathing costume apart from saying "This isn't the beach." His blind adherence to the nebulous concept of "policy" is what is criticised by Sammy, whose act of quitting questions such a strict adherence which is not apparently based on reason or logical thought.