The nation was unethical due to the genocide regardless of if they provided a surplus of water or not... So the USa cant be ethical regardless of the water, and them not being ethical is unrelated to the fact that we arent providing them yet another source of water that they wont build the infrastructure to utilize.
Afterall even if we let them have access they would still have to build the infrastructure to collect it, which they have shown they would be negligent to do.
They already have water, they just dont have access to that water. So providing them another source of water they similar wont build access to wont fix that.