Why do cultural moral norms exist?

[write4u]

@Markus7

This view is supported by the science of morality. The “moral” reaction to guilt is to use it to motivate not repeating what you did wrong.
You would be acting immorally if you allowed your guilt to consume you so that you are no longer helping others and treating them fairly and thereby doing good in the world.

That is a true statement, but that does not make it moral. Most often it is the others that are accusing you of being guilty of something,
Most religions and all cults maintain power that way.