But, returning to the specific circumstances, that's really not where women SF writers are anymore, and hasn't been for, jeez, thirty years. Because, seriously, a whole issue of Realms of Fantasy (or any other magazine) is, what? Six stories? Seven stories? Ten if they're small? I guarantee you there are more than ten women writers doing excellent work in sffh. As Cat says, a Very Special Issue is tokenism. (It also suggests, subliminally, that women writers are fragile flowers and can't compete with men head-to-head, that our stories wouldn't be good enough to fill a whole issue without this special enclave, like we're a rare species of owl or something.) It neither causes nor promises fundamental change in the way a magazine is run or the way an editor makes decisions.
I should say here that I don't know what the motivations are at RoF. For all I know, this is a sincere attempt to cut through the male-dominated bullshit and champion the cause of feminism and women writers. And it's a very attention-getting way of doing it. I'm just not sure it's the best way.
[ETA: as jimhines kindly points out, Douglas Cohen explains some of the editorial thinking in the second comment to the announcement.]
*Not, of course, that women are a numerical minority. Tra la.