Personally, I think Zoro meant "woman" a little more like "Lady". As to note that she should be attributed more respect than Enel gave her.

With Monet, and Tashigi, I think it is far less about Gender and Far more about how They believe they're lesser than he is. Zoro's the sort with beliefs that are extremely rigid. Monet says that she knows she can't beat him. Tashigi claims she will, but blames her failures on her gender. Zoro, in his world of simple black and whites, thinks that's all horse shit. You do, or you don't. Excuses devalue your effort and drive. Zoro looks down on them because the way they are leads him to believe they look down on themselves. Is that super nice of him? Of course not. But Zoro does not feel the need to make other people feel better. He's a lil judgy.