The real issue here is whether or not he has leeway to grant or withhold the license. If he DOES have the ability to use his judgment, than he should be able to deny the license on these grounds. No one would fault him for refusing permission for a teenager to marry a significantly older person (in my state, you need permission from a judge to marry if you are only 16), but that is discrimination based on age. The judge is not actually practicing discrimination, since he marries black people, and white people, and apparently does not refuse permission of more blacks than whites or vice versa. No can argue that he is not denying the black party something he is also denying the white party. He is treating them equally.