>While looks unlikely. How would such a society would enforce no slavery if people still profited from having slaves? It should punish those that do to prevent that (and thus it couldn't fully embrace the non-violence thing).
I probably didn't make the best choice of words, but by "a society/governance structure that rejects the notion of using violence to enforce certain beliefs on others", I meant a society where violence is rejected in general; slavery is the slaver enforcing their beliefs on how the slave should behave on the slave, and they have to use violence for this, or else the slave would escape.
You're right though that maybe this would only work if every member in the society agreed not to use violence. There could be alternatives though, e.g. ostracising the violent person - if nobody else in society interacted with them, they'd starve. Or building a literal wall around the community and not letting the violent person in. Allowing people some degree of violence in direct self defence, e.g. restraining the violent person and pushing them out of the community.
>Well, if the "man watching the drowning man" was punished for his non-involvement, then future drowning men would be better off. So it might seem like it's a totally passive harm, but it actually affects the future of what's acceptable.
This only works if there's somebody who sees the person letting the drowning man drown (and if there's somebody else there, why didn't they save the drowning man themselves?). Even then there's no guarantee: maybe if such a law existed against not helping downing people, people who didn't like helping others would just stay away from rivers more, to reduce their chance of ever being in that situation in the first place.
Slavery is based on using force to have others do your work, serve your interests -- not in enforcing certain beliefs in others. So it's not enough to have a "a society/governance structure that rejects the notion of using violence to enforce certain beliefs on others", but also to have a society that it or individuals also don't use force to serve their private interests.
While looks unlikely. How would such a society would enforce no slavery if people still profited from having slaves? It should punish those that do to prevent that (and thus it couldn't fully embrace the non-violence thing).
>(A society rejecting violence in the absolute sense would barely even support notions of property, yet alone slavery.*
Is such a society possible? Only if it has everybody's agreement (not to be violent, use violence when it suits them, etc). Else the society would have to use violence itself (that is, some kind of police) to maintain the non-violence in its members.
>The difference stems from the fact that neglect is a passive harm; if the person doing the neglect didn't exist, the neglectee wouldn't be in a better situation. If the man watching the downing man didn't exist, the drowning man isn't more likely to be saved. Violence is an active harm: if the person doing the violence didn't exist, the victim would be better off (at least from the victim's perspective); if the slaver didn't exist, the slave would be better off.
Well, if the "man watching the drowning man" was punished for his non-involvement, then future drowning men would be better off. So it might seem like it's a totally passive harm, but it actually affects the future of what's acceptable.
(Not to mention that the drowning man, assuming he eventually managed to escape, would probably rejoice in seeing the "man watching him" getting punished for not trying to help him).