Wut? Just the opposite. He has said over and over, "This election is about competence." He is secure on his long history of having hired and promoted women to high positions throughout his career, and his plan to leave the major direction of his company in the hands of his daughter.
I think they mean “he didn’t run for cover like Republicans are supposed to when she went after him with the gender card. He attacked her back with on the same lines and we don’t know how to respond to that since it’s never happened before.”
He didn’t make gender a big issue until she did. Then she dropped it and so did he. If she brings it up again, he’ll hammer her with it again.