It is not a comment on the religious/philosophical validity of the belief as I initially understood it.

Just that for a specific belief to survive, some number of members need to survive to pass it on to the next generation, which if their beliefs bar them from killing or violence requires them to rely on people who aren't.

I don't think this comparison to early/mainline Christianity is entirely fair. It was murder, not "just" killing that was prohibited by their values.