Marvin Harris — American Scientist born on August 18, 1927, died on October 25, 2001

Marvin Harris was an American anthropologist. He was born in Brooklyn, New York City. A prolific writer, he was highly influential in the development of cultural materialism. In his work he combined Karl Marx's emphasis on the forces of production with Thomas Malthus's insights on the impact of demographic factors on other parts of the sociocultural system... (wikipedia)

The commandment 'Thou shalt not kill' does not say it's O.K. to kill some people and not others.
Every theory presented as a scientific concept is just that; it's a theory that tries to explain more about the world than previous theories have done. It is open to being challenged and to being proven incorrect.
Pigs prefer to wallow in clean mud, but if nothing else is available, they will frequently wallow in their own urine, giving rise to the notion that they are dirty animals.
The answer has to be sought in the material conditions of the production and utilization of cattle in India compared with the production and utilization of cattle in other parts of the world.
Yes, a general principle that comes out of research behind Good to Eat is that there are no world religions that have acted to decrease the potential for the nutritional well-being of their followers.