How many races are there? How many genders are there? How do we differentiate between them? Yet we're supposed to take these nebulous categories seriously enou

How many races are there? How many genders are there? How do we differentiate between them? Yet we're supposed to take these nebulous categories seriously enough to treat people differently based on these characteristics that can't even be properly delineated or defined? If these things exist on a spectrum and can't be clearly defined (even worse, purely self-defined), then there is no logical argument to categorize people into these categories for any use whatsoever.