If the creator of a fantasy series can dream up an army of self-resurrecting zombie immortals he can damn well dream up equal marriage rights, and if he chooses not to do so then that choice is meaningful, as is our assumption that the default setting for any generically legendary epic must involve really rather a lot of rape.
A lot of people have taken this post by Laurie Penny to be saying either that she thinks Game of Thrones endorses its setting, or that she thinks fantasy has some kind of obligation to present a vision of a better world than our own. But the last clause get’s to the more complicated point she’s actually making, and to what’s wrong with Game of Thrones. The problem with the show is that it assembles a bunch of fantasy cliches, many of them racist and sexist, and distances itself from them with a dash of simplistic cynicism (sometimes bad things happen to idealistic people!), which allows it to disavow these tropes while still relying on their narrative power. I don’t know what’s going to happen to Jon Snow or Daenerys, but they’re not going to die of dysentery surrounded by people who have know idea who they are, because, dramatically, that wouldn’t fit the heroic narrative the show depends on; the show continually comes up with some supposed “realpolitik” reason to prevent something unpleasant happening to a character we like. Now, I quite enjoy fantasy cliches and the show has some charismatic actors who manage to make the cliches compelling, but because the show relies on us being engaged by these tropes while disavowing this enjoyment, the racism and sexism it displays remains genuinely racist and sexist, and doesn’t manage to function as a critique.