It would impact the main food production area of the US.
The West and East coasts would suddenly find themselves being unable to afford feeding their underclass populations.
Was the author of Soilent Green a liberal? Also those who survived the Andes plane crash by eating their dead were mostly medical students. If at 80 I were to died from such a disaster, I would ask my family and friends to honor my passing by using my nutrients. Who would be more able to think that way, liberals or conservatives?