[badcppdev]

You are working from an incorrect assumption about your choices.

* Doing nothing is unjust.

* Providing material aid and luxuries to the slave holders/cannibals is unjust.

* Using your presumably superior force to stop murder is not unjust.

[K0balt]

It gets murky fast when the culture itself is the problem and not just some bad actors. When you use coercive force to fight an ideology or a culture, and the ideology or culture makes up the majority of the demographic, you end up with very messy situations that often create more suffering than you were trying to alleviate.