The idea that people who aren't so sure about this as you are have isn't that telepathy is going on. It's that if this sort of mind-state cloning is going on, you might no longer have grounds to expect to wake up as the physically original instance of yourself with 100 % certainty after the cloning procedure.
People are made of atoms, and so far we haven't found any magical quality beyond physically stored memories that gives us reason to think a person at one point in time is the same as a person in another point in time, including ourselves as the person. With the mind-state cloning going on, at some point in time there is going to be one present person with a past person's memories being unsurprised at not having ended up as an upload, and another present person with the same past person's memories being quite surprised at ending up as an upload despite remembering having been a physical person who expects to continue living as a physical person. I'm not quite sure what kind of definition of self would let the past person maintain a justified 100 % expectation that they will end up as the non-uploaded version of themselves in the future.
People are made of atoms, and so far we haven't found any magical quality beyond physically stored memories that gives us reason to think a person at one point in time is the same as a person in another point in time, including ourselves as the person. With the mind-state cloning going on, at some point in time there is going to be one present person with a past person's memories being unsurprised at not having ended up as an upload, and another present person with the same past person's memories being quite surprised at ending up as an upload despite remembering having been a physical person who expects to continue living as a physical person. I'm not quite sure what kind of definition of self would let the past person maintain a justified 100 % expectation that they will end up as the non-uploaded version of themselves in the future.