ok so like, even in a multi species setting:
The culture is advanced enough to take prisoners. And they are guilty and the sentence is death. Whether it it sacrifice to the gods, hand the, to the gladiator pit, they die somehow. And then, the culture decides not to be wasteful or something and use their flesh as food. Who do they give it to? The peasantry? Livestock? Who the hell wants to eat the meat of criminal scum? Why the hell would a princess be in a position to eat criminal scum, when they are likely wealthy enough to eat anything they want.