Speaking critically isn't behavior that's necessarily desirable or encouraged in women. It's a similar question about why there aren't more women in finance. You can't be worried about whether people like you. You have to feel comfortable being fair. And sometimes fair isn't sweet.
That's the Boston Globe's Devra First in Grubstreet's great roundtable of female restaurant critics talking about hiring discrepancies in their field. Elsewhere: read Besha Rodell on the topic at LA Weekly, who found that around the country, "the number of male critics is more than double that of female critics," and also relayed this horrific tale:
I'll never forget my welcome into the food-writing world as a young critic — my first time at the James Beard Awards. At an after-party at Momofuku, I remember being introduced to a group of men in their late 40s, all established names in the food-writing world, all wearing tuxedos and looking dashing. I was thrilled to be in such company, these men whose careers I aspired to emulate.
And then one of them glanced at me, saw my "nominee" badge still affixed to my dress, and scoffed, "I think you can take off your badge now." All four or five of the men standing around guffawed. The message was clear: Go home, little girl, and let the grown men talk.