If they choose to believe that non-interfering RF is causing them great harm, what is the harm in allowing them to hold that belief? It appears they are only harming themselves in so doing; outsiders can choose to visit other towns instead. Make no mistake that I don't agree with their ideas of Wi-Fi causing harm to humans, but I also don't see how their idea hurts anyone outside their own group.
Ignorance is harm in and of itself, let alone the idea that, if they choose to blame something on an incorrect source (cows are dying because witches) they remove the possibility of finding and fixing the actual problem. (Cows are dying because contaminated feed, water, disease, whatever).