I think Fussell'd peg banning swearing to act higher class or more professional as a deeply middle class thing to do. Part of their trying-too-hard while missing-the-point tendencies. Avoiding out of fear of punishment would be more mid- and low-prole (high prole being too independent to care much about the whole matter).

Imposing it from above might be an attempt to force/encourage middle or low/mid prole attitudes in one's workers in general, and to make people with such attitudes feel elevated by the notion that "we're so much more professional now!"