There are. If I had to guess, I'd say they're probably a small minority, but they're still here, even if they mostly lurk.
But that's pretty irrelevant because no one uses VGC as some sort of dating service and whether an opinion is coming from a woman or a man really shouldn't make a difference as it pertains to 99% of what's discussed here.
Barring the rare gender discussion thread, there really isn't any point in announcing something along the lines of "my opinion, as a woman..." because it doesn't matter. It neither further validates nor lessens a given opinion.