Marissa Mayer was a terrible CEO. Period. She was responsible for a string of 48 (!) (mostly) terrible acquisitions[1], banning remote working[2] and wasting
company money on things like motivational books[3] or lavish parties[4].
She is getting more flak than the other terrible CEOs, but IMO it isn't caused by the fact that she's a woman. At least not directly.
Back when she was appointed as a CEO, media were treating her like a second coming of Jesus (which probably indeed was caused by her gender, she was a perfect role model for feminists). That set expectations bar really high, and when she failed to deliver, people turned against her.