I feel like if a child with a similar level of cognition as the cow harms other children, most people will say they have no moral agency yet, and will still see harvesting their leather as immoral.
There are two ways to resolve that inconsistency…
And the good thing is, when demand for (human) leather is higher than supply, people will just breed some more humans, keep them on farms, use their labor and sell their leather. With nothing going to waste, just the beautiful circle of life.
We’ve gotten quite efficient at doing that so there’s plenty opportunity to have more jobs, make a profit and to provide a product at an affordable price point, at the same time, all with human leather farms. Just have to compromise on welfare and sustainability step by step for more profit, but humans are already really great at ignoring such things when it’s advantageous to them, so most won’t ask any pesky questions anyways. We just have to normalize human leather (from factory farms) and everything will be great.
And when it’s the only way to keep their family from starving, for example, people will consent in droves, securing supply.