Most conduct that should be illegal is also immoral, but there are a whole lot of actions that are certainly immoral and should not be illegal. This employment action is in that very large category. I'd rather see decent patrons abandon this guy's business and allow the free market to punish him, rather than using government force to take his property, when he is making a work uniform decision and an employment decision that both should be within the scope of his control.
Having been found guilty of "racial discrimination" in a hiring decision (I hired the Hispanic man with the higher degree and better attitude and aptitude for the work but rather foolishly advised a white applicant that an advanced degree in the field would make him more competitive. Since blacks and Hispanics are under-represented in that degree field, my comment proved racial discrimination!), I am not terribly fond of the way employment laws are enforced. I no longer give any feedback to job applicants, so the rat who complained about me won some money, and all future job applicants lost out. I don't see that as a gain for society.