Once any body is fully composted, it is not a body anymore, it has returned to being earth and it nourishes the plants that feed the mammals and us. That's not cannibalism, it's literally the cycle of life on this planet. Every spec of dirt you stand on was once part of something living. The only objection I have is the trace toxins that would come from humans who have been on pharmaceuticals and vaccines all their lives, these unnatural ingredients probably won't break down in compost for many many years, if at all.