If I said that only my mind exists, and that others do not have minds or their own will, people would look at me like I am nuts. Yet people are often saying: I cannot understand how someone could do that - where "that" is some horrific deed.
What the person really means is: I could never imagine myself doing something so dastardly. Yet that seems like surprise that other minds exist. Unless, I guess, if people think that other minds exist - they just happen to be duplicates!