Killing child pornographers that would fight to continue producing child pornography is not a controversial or complicated idea. Identify the group, get rid of it. If they won’t stop voluntarily, kill them. That’s direct action and community defense. Cornerstones of libertarian ideology.
First, by what authority can a libertarian society kill another? Should there be some sort of trial? Or do you propose we just ride and kill anyone we deem undesirable? And where’s the line? Certainly it’s pretty easy to argue that child porn producers and slavers might qualify but what of others? How do you deal with the majority falling into fascism and deciding “You know what, the Catholics are a plague on society and we should eliminate them.”
I’m not going to get into the cult bit, that’s an entirely different conversation.
You should, because cults are very real things that would thrive under most libertarian models. They also show a real big problem, with unchecked power it’s pretty easy to seriously abuse societies members. Even when they technically have the freedom to leave. What happens if we remove all checks to cults? Do we decide to kill them too when the decide not to continue?