Dude, who cares, it's fantasy.
If there can be dragons who co-exist with people, there could be black people.
If there can be people with powers over elements, there can be gay people.
If there can be fictional places, there can be non-binary people.
Besides, gay and non-binary people DID exist in medieval times, even if not openly. Besides, wouldn't it be too restrictive to not allow choices to be gay/bi, non-binary, or black.
Not every story in the past that includes the above have to have discrimination, they don't always have to be realistic. Let gay, non-binary, and black people exist in medieval fantasy.