Your thinking is skewed. Ordinary logic dictates, by default, that the base-level "starting point" of any assumption to be proven is 'zero'. It is illogical to
assume the existance of something, and demand from another to prove that it
does not exist ( or, never existed ); rather, the "proof" must be in that it
does ( or , did ) exist. ( i.e., that something actually occurred )
I deny that we have been to pluto. Are you saying that it is up to me to prove that we have not been there?