[Frazmatazz]

"if an employer wants to not hire you because of your race/gender/nationality etc, it can do it anyway in a later stage"

First, you're increasing the probability of discrimination by making it possible earlier on. The number of people that could exclude you goes up; e.g. the initial, possibly external, recruiter (who is screening hundreds of candidates) who would never otherwise have seen your face, can now discriminate on appearance.

Secondly, people are less discriminatory to people they've actually met and gotten to know somewhat. A picture of an anonymous person, with very little other information to go off of, may affect someone's judgement quite strongly; whereas, when you actually meet and talk with someone, have a lot of other information about them, and they are no longer anonymous, physical appearance will have less influence.