Game theory, in specific a coordination problem: If every business in town discriminates against purple-haired people, for example, the owners of the one busin

Game theory, in specific a coordination problem: If every business in town discriminates against purple-haired people, for example, the owners of the one business to break ranks leave themselves open to harassment up to and including being murdered. Even if no business wants to discriminate, being the first to make the move sets you apart, and open to retaliation from the consumer base. The government mandating hair-color-equality dissolves the problem very neatly.