Morality aside, a big issue would be the butchering of the meat. Meat rots FAST when the animal dies. That is why one of the first steps in butchering is to start draining the blood as soon as possible.
So right away, all people that die accidents of any sort will be disqualified from being eaten.
What does that leave us with? The diseased and the old (usually one and the same). Unfortunately, diseased meat doesn't taste good and has health issues associated with it. And old meat is, well, old. Meat from an old animal is just not very tasty.
Pretty much the only meat that would be eatable would be that from people who die on the operating table from a non-viral/bacterial infection who are younger than 40 (heart failure, brain aneurysm, etc. Not cancer).
And even then, Humans don't have the large amounts of muscle like other eating animals do (cows, pigs, etc) Even the strongest of us are pretty bony compared to other animals. So really, you save nothing. Most of the meat would be inedible (like 99%

because it is old, diseased, or couldn't be drained properly. The portion that would be edible will likely come from fatties with low muscle mass (not tasty). And then there is the whole morality issue. For some strange reason, people don't like the idea of having loved ones served up on a platter after their death.