Yes, to o it without fear of a false social order it does need to be approved by society, but it can be lawfully done in moral law even if the social normative order doesn't yet recognize something as immoral and you act to stop the immorality. Slavery was legal and part of the social order, but to stop slavers would have been lawfully moral regardless of the social order.

You have the authority to act morally in any devolved society that fails to recognize morality, but they won't necessarily like it and may hurt you through false perceptions of thinking you are the violent when when you aren't. Even if 95% cooperate to enslave 4%, if 1% recognize morality and act int hat authority, they are lawfully (morally) doing so, despite not "legally" doing so.

Morality (Maat) is the pillar and foundation for realer, truer and higher life indeed :)