Great question! I think problems like that tend to solve themselves. Do they work in that community? Do they have family or friends there? Do they shop there? At least in a voluntaryist community, people and businesses are free to disassociate. So anyone can "vote with their dollars/association" against the person spewing the stuff they don't like to hear. Or just not listen/go away. If the hater follows them onto private property without being invited, then - of course - something can be ethically done to the hater, though I would hope for de-escalation of violence, rather than escalation.