It’s hard to do well, but I disagree that it’s a slap in the face or a low blow. The gender swap of Starbuck from Battlestar Galactic was seen as sacrilege by fans, but she became one of the highlights of the show. Miles Morales was a creative way to do a race swap for Spider Man, and the narrative is richer for it. Jason Mamoa turned Aquaman from white to Polynesian, and the depiction was better than ever. Would Nick Fury be better as a white guy, as he was originally for decades, instead of Samuel L Jackson?
And then there are all the “swaps” that happen before the first day of filming, like Ellen Ripley, Sigourney Weaver’s character in Alien, who was originally (edit) going to be cast as a man. This was “controversial” at the time, with people decrying “political correctness”. I would not take “causing controversy” as a reliable indicator for whether something sucks.
Edit: point taken about gender neutral script. See discussion below.