They're not. I lack empathy completely, and I thoroughly enjoy watching others suffer. If I see people crying, I have no idea how to react or what to do.
Women are seen as weak, fragile, feminine, sensitive, docile and child-like. Men are seen as strong, dominant, aggressive, masculine and emotionless. Seeing another gender take on aspects of the other is seen as entertaining and somewhat laughable. Men attacking those who are seen as children, weak and fragile is known as unfair and terrible - just like assaulting children.
If people didn't see women as weak and stupid, people would react differently. Many women have no empathy since the beginning of time, so it isn't caused by Feminism.