It's not really utilitarianism at all. There is nothing in utilitarianism that says round up some undesirable group and kill them so a few wealthy people might get organs so they can live. The greatest good for the greatest number of people. What is the consequence of these actions, well first murder. That leads to no happiness for the murdered, their families and loved ones. The people receiving the results of that murder, when aware that they are culpable in murder and should probably be imprisoned for it, would not be very happy with the consequences. So no this is not utilitarianism. It's completely immoral and shows the sort of moral turpitude of that situation.
But the assumption you're making is that they're being killed in order to be harvested. While this is certainly a perverse incentive that such a collection system is creating, I don't find where the article mentions that organ harvesting is the reason for their collection, but mention their execution for dissidence and ethnicity.
If those victims were to die anyway, it does become somewhat of an utilitarian problem.
And if it is, the gaming issue that would bias decisions towards executing the prisoners instead of "lighter" sentences due to the "gains", which creates a vicious feedback loop ; and the fact that overall the gains in that system are not just people surviving, but also captors getting rich ; should point clearly to the vice and undefiable corruption that make it undeniably unethical.
That and the fact that a regular human with any ounce of love or humanity in its blood should feel how wrong and disgusting this all is
