Why do men and women need to be the same? Isn't it ok to be different?
There is a segment of the population that is physically one gender but feels they are actually the other. If we weren't that different, nobody would go through the massive physical alteration.
The size of the population that has gender dysphoria is irrelevant.
The reason for this is that they're (a) always the same and (b) always degnerate. (a) makes threads unsubstantive and (b) makes them uncivil. Civil, substantive conversation is the whole idea of HN threads—however rarely we may actually achieve it—so you could hardly do anything that more violates the site's values, even if you didn't mean to. Not meaning to makes it more insidious in a way.