It’s a sensitive topic but white and black people are genetically much more seperated than black and white rhinos which we are happy to describe as separate species.
The term isn’t outdated because it’s incorrect, it’s outdated because if you start saying different groups of humans are literally separate species it really feeds in to the racist agenda.
Edit: Given the replies, it appears that I may well be wrong, I remember reading it somewhere but I can’t find the source nkw. I’ll downvote myself but leave the comment up because it enables others to learn from my mistake