The proposition is quite an oversimplification.

Morality comes from the term Mores.
mo·res
/ˈmôrāz/
noun
plural noun: mores
the essential or characteristic customs and conventions of a community.
"an offense against social mores"

So if it's "right" to kill your neighbor and eat him...then there will be no "guilt associated with this behavior within that culture or community.

The #religulous got this confused...and assumed primitive was without "mores" so they went about "civilizing" primitive cultures.

As it turns out...they had "mores" all along...many far more "critical" than the #religulous ones.

[jstor.org]