You would be right, but you would have to show that there are murders taking place for the direct production of snuff films, that there are (significantly) as m

You would be right, but you would have to show that there are murders taking place for the direct production of snuff films, that there are (significantly) as many murderers feeding snuff film addicts as there are child pornographers feeding child porn addicts. Put simply, snuff films don't encourage further murder (not through the audience, and not indirectly from demand).