This sums it up for me. An invitation can be open to everyone, but the activity they're being invited to will determine what sort of people show up. When I read, "Come and do whatever you like to an unresisting human who will sit still for six hours," I immediately turn away--not just because I'm not interested in "doing whatever I like" to a person, but because I don't want to be in a room with the crowd of people that I imagine would want to do whatever they like to a person.
This sums it up for me. An invitation can be open to everyone, but the activity they're being invited to will determine what sort of people show up. When I read, "Come and do whatever you like to an unresisting human who will sit still for six hours," I immediately turn away--not just because I'm not interested in "doing whatever I like" to a person, but because I don't want to be in a room with the crowd of people that I imagine would want to do whatever they like to a person.