Most people - just going by observation - appear to advocate policies based on who they actually are rather than on abstract principles. You're going to have to

Most people - just going by observation - appear to advocate policies based on who they actually are rather than on abstract principles. You're going to have to live with them voting. Furthermore the argument that it is a bad idea isn't even strong. The veil of ignorance is powerful and interesting but voting is about different cultures negotiating to make decisions. That all but guarantees there will be different conceptions about what is fair that are not the veil of ignorance and those need to be respected. They aren't sociopaths, they just don't agree with you.