Personally I wish they had never introduced the whole Spock/Uhura thing- I think she is a strong character who never needed to be defined by who she is with.
Kirk and Spock are supposed to be very strong characters as well but many people including the writers still think that they should be defined as people by their friendship and they even have Spock prime saying that. Many of the opponents of the Spock/Uhura relationship are in fact people that feel she's a threat to
that because if Spock has someonelse besides Kirk somehow, someway (according to them), it takes away from the fact that Kirk should be the one and only "completing him" and making him a whole person.
People, including actors like Chris Pine, always talk about how these characters cannot function as human beings without the other and I cannot imagine what people would say if the same things were said about Uhura.
So it's kinda ironic that people think that in a franchise that is mainly based on a friendship that defines the characters it's Uhura the one defined by her relationship with Spock and further ironic is that they consider that diminishing of her character all the while the same identical thing (and "worse") is considered the biggest appeal of the K/S friendship for many.
IMO It all comes down to the fact that according to some women cannot express love and feelings because if they do that they're considered "weak". On the other hand there is this very radicated patriarchal idea in the star trek fandom in particular that men being defined by their interpersonal relationships are good story telling and character development (maybe because it had always been like that) Only men are allowed to show feelings without being made weak by them.
Take how McCoy is mainly defined by his friendship with Kirk in nu!trek as almost the totality of his most important scenes are about his friendship with Kirk and yet no one complains about that making McCoy weak as a character.