i think cannibalism is a fine barometer of cultural relativism and lingering western chauvinism. to take the most charitable approach to op1, 'ritual cannibalism to honor the dead' is quite different from the consumption of enemies or strangers--for which our objection would be the violation of those non-consensual victims' consent or rights. but the Fore community in which Kuru famously spread did not practice that, theirs was the consumption of family/community members after natural death. i can't format an objection to that, besides the associated healthrisk---which modern medicine could probably prevent if applied to the problem. the Kuru outbreak actually killed that tradition so it's kind of academic to debate, but i think it's important examine knee-jerk demonization of foreign ritual on honest terms, and to apply a consistent standard to all sorts.
for a more practical question: should a religious practitioner be permitted to fast to death? a voluntary religiously-motivated suicide gets very different billing based on the context, and whether that's justified should be examined. maybe one is permissive of a fasting death or a self-immolation, but not an allegedly voluntary sacrifice, or a jonestown? what are the limits to religious freedom and bodily autonomy, and are those informed by a christian socialization or a materialist basis?
endnote: no, lol to the incest. my actual stance on religion is full abolition before someone twists this into support for mostly dead religions, this is about racist and chauvinistic attitudes that socialists are not automatically immune from
I do not know if the culturalist opponents of the real world and its evolutionary trends, understood as Americanization by some and Westernization by others, can be described as rational. Confronted by the threat of Americanization, some defend unique "cultural values"...This is a dangerous situation, and the danger is enhanced by adherence to the principle of irresponsibility. It is dangerous because the (capitalist) system has reached a stage characterized by the monstrous power of its destructive capacities. As I said above, the system is capable of destroying human beings, nature, and whole societies.
Samir Amin, Eurocentrism.
They certainly aren't rational here...
If you start from a culturalist critique and not a materialistic one, this is what happens.
As leftists we shouldn't question countries where women and minorities are oppressed and have their rights taken away. The oppression is part of their culture and we should never question any culture whatsoever.