I can be a fan of anyone I want, including anyone surrounding 1D that aren’t strictly the boys.
If I want to be a fan of Gemma, I can do that. If I want to look up to Eleanor, I can do that. If I want to be a fan of Joe Shmoe standing on the street corner, I can do that too.
Why does it bother people so much that the girlfriends have fans? There are YouTubers who make videos about nonsense that have fans. There are bloggers who write about clothes that have fans. Why are you so offended by the idea that people might look up to a group of girls who are constantly harassed for their relationship and still manage to handle it with grace?