I don't think it's because men are less complete human beings; though what I think you mean by that may not align with what you meant by that.

I think it's to do more with the identity of manhood being defined around negative space. In other words, men define themselves by what they are not rather than what they are, more often than not.

They're NOT a woman, which is bad. They're NOT weak, which is bad. They're NOT a pussy, which is bad.

Manhood is defined by demonizing the other, labeling it as bad, and destroying any hint or alignment with the label within themselves. All based on abstract concepts over discernable reality.

Creating a reality from an abstract that is maladaptive long term is a very very human thing to do. More often than not we are the architects of our own demise and it generally boils doen to how we choose to weird that ability to abstract.

Choices are made. Fallout ensues. Round and round we go.