I think when it comes to this kind of issues we have to weight of coises. Yes, killing hippos is kind of sad, but also is losing others species because of them. And in the scale, native species should be given priority.

You don`t have to shoot all of them. Just allow hunters to kill like 50 of them, and with the money from the licenses, capture other 30 or so and send them to zoos or back to africa in their native enviroment.