Except in very particular situations (Actors… that’s pretty much it) I don’t think employers should be allowed to have literally any opinion on your appearance past like, “don’t literally be covered in dirt.”
To be honest, interviews should be blind with fake names and voice modulators. On top of the obvious sex and race reasons that you shouldn’t be allowed to discriminate, I don’t think employers should be allowed to ban things like piercings, tattoos, dyed hair, weird hairstyles, etc.
Obviously you shouldn’t be allowed to fire a black girl for having light hair, but I don’t think you should be allowed to fire someone for having a green Mohawk and a septum ring either. Fuck off, it’s none of your business.
I appreciate my line of work because I can wear fishnets and makeup and short shorts while in the office, while in the same building with poor souls forced to wear button ups and shoes which give their footsies wounds.