Why the resistance to "fan girl" Ms. Marvel?

With the upcoming release of Square Enix's Marvel Avengers game, some early clips have surfaced showing Kamala Khan, aka Ms. Marvel, standing up to some bullies who are trying to "gatekeep" her fandom. The scene, which plays out much like many other anti-bullying scenes from educational television, has had a strong negative reaction from comic fans (as opposed to my reaction which was a feeling of exhaustion at playing through endless cutscenes)... and it brings up the topic, why is Ms. Marvel such a lightning rod of a character, and where did Marvel perhaps go wrong in marketing her?