Why do we need to establish a basis if it’s all made up anyway? For what purpose?
Okay, so then why do we have a word for woman? What is the intention of that category? Is it really necessary to define anyway? If not, why does it matter what a woman is except its what she calls herself?
We have a word for woman because it is a useful descriptor. The intention of the category is to presuppose useful information about a person. In some situations it is necessary to define. No need to answer the if not question.