There is a sound biological basis for treating children differently than adults, ethically, in some (but not all) cases: because children are not fully developed mentally. This is the same reason why we might make similar distinctions for those who are heavily mentally handicapped or low-functioning.
But I believe that a grown woman and a grown man, all else being equal, have the same general mental ability; and the same is true with someone perceived as black or white. While there are real differences in a woman or a man's brain chemistry, or in the blood chemistry between someone of African versus European origin, and so forth -- and these differences are significant in certain contexts -- they aren't sufficient to make two categories of "right and wrong," or to say that women or men, or blacks or whites, are somehow not fully accountable for their actions, in the way of a child or someone mentally handicapped. To say otherwise is, imho, itself sexist/racist.
You make a lot of (unwarranted) accusations as to how people who disagree with you don't use their brains, or "can't comprehend nuance," or etc., but to me it looks like maybe you're projecting a bit. There is nuance here that is seemingly lost on you, and important difference between categories like gender, race, age and intention (which speaks to the difference between manslaughter and murder, and is its own kettle of fish). I don't expect you to understand this all at once, because no one works that way, but do give it some more thought over time, and try not to be so insulting as you discuss these things with others. You may need their help to grow.
I make no unwarranted accusations. Harping on about double standards without care of cause & effect is nonsensical. Its like saying a business that only employees disabled people is discrimination and should be treated the same as a business which only employs white people. Disregarding gender, race etc in these discussions is frankly daft. Sorry if my tone rubs you the wrong way, I just have no patients to continually explain how the weight of actions are informed by social surroundings and context. Not on here anyway where people immediately run into "well if a man said this...", well if Woman were constantly sexually harrasing and hounding men we could maybe make a valid comparison. Have a nice day, I'm lovely in person.