Because, you know, people were so dumb until social-constructivism landed on Earth like the Messiah no-one expected. And we need to be re-educated. Or else.
What baffles me most is the insistence that one can build any kind of objective distinction based on subjective experiences, that is, what one feels. We're all capable of sadness, joy, excitement, and what not. But we can not build any kind of categorization (read diversity) of people based on these concepts/states of mind. I don't identify as sad, although I'm sad from time to time. No one does. Companies can not be forced to hire more sad people, for the sake of diversity. Yet, now, it's compulsory to have more people hired because they report some sort of internal and inaccessible state of mind which they express using words used for categorizing people based on the shape of their genitalia.
The only thing that's funny is that on a thread about lab rats reacting differently to male or female lab workers, people feel the need to start a holy war about topics as pointless as this one.