Homeopaths are careless and other people die.
I would make an analogy to veganism. Vegans as a whole are more intensely interested and passionate about their health and what they eat than your average healthy omnivore. For that reason, they're also more likely to proselytize and promote their ways to others. It's my belief that in doing so they potentially bring harm to themselves and to others. Do I think they should be engaged in vigorous debate and their arguments refuted to the best of scientific knowledge? Yes, absolutely. But I don't think treating them as idiots or malefactors is well-deserved or productive.