Saying anything bluntly will guarantee that contact will be severed and further influenced ended. I handle our situation with subtle philosophical discussions. I ask questions instead of making statements... and lead them to see what the answers are for themselves.
Maybe the lesson they need is that lots of people don’t want to be around that at all. And would you let them in your door? Would you drive to someone else’s house to this twisted spectacle?
I just don’t see engaging here. And last, they aren’t exactly tippy toeing around you, so why do you need to be any less blunt?
What would you say if he was coming to the house to say he likes child porn, wants to snort crystal meth, etc?
This is someone coming by to say they want to mutilate their body.
I don’t think there’s a delicate approach to be had there.