Why? Because your brain makes you feel like it is not a valid answer. If life were all mindlessly natural we'd be doing nothing but killing each other in the most brutal ways while competing for mates. Civilization was made to escape those things, because our lives are worth more than some pointless game of dominance and natural selection. So how can you sit here and argue that there is nothing wrong with harming even young boys because their natural worth is lower than girls'? You see people as resources, utilities, and tools, not people. You dehumanize people and view them as objects. Therefore to you, abusing the less useful tool does not matter, because it has no value in your eyes. It is like throwing away a stick. But we are not robots, but prisoners of the flesh. So for the time being our selves must take priority over the game of life.