Because this media narrative is bullshit. It popped up out of nowhere, without a damn shred of any verifiable evidence, and has already gone from the usual clickbait fraud outlets to local news casts (e.g. KARE-11's "Bringing The News", in Minneapolis, did a segment on this and all they did was read a PR script)- so expect it where you are if you're in the Anglosphere soon.
Meanwhile, the worst that's actually going on it "Please don't make her suck like Rey.", and that's a concern about the execution, especially the writing. That's the reality here: concerns that the team delivers a quality product. Sensible folks in the media, such as this Charles Spiering at Breitbart, have picked up on this.
The problem is that there IS some agenda here at work. Disney IS SJW-converged, and they ARE pushing the Feminist agenda with these casting decisions. When you put pushing an agenda above producing a quality product, you get shit like the Beandog debacle regarding Balder's Gate, and that does nothing but further degrade the brand and degenerate the business behind it. In short, you're killing yourself if you do that.
And it's not like the SJWs don't lie to push their agenda:
Who did it b̶e̶t̶t̶e̶r̶ worse? pic.twitter.com/lEiD7edAlF— Matthew (@Mattaconda) April 6, 2016
Those are examples of failed attempts at fraud to firm-up a narrative push. We're right to be skeptical.
So, for now, hope that the producers and key players in Rogue One don't have their heads so firmly up their own asses that they fail to do good work. A female protagonist is fine, so long as she's competently executed and the artwork reflects the Natural Law of the real world; failure on either aspect will do more harm than good for all concerned.
And that's the real concern here: the degradation of something beloved to preach a dangerous dogma to an unwanting audience.