The joke is that there are some people who think that by uploading themselves into a machine "to live forever," their consciousness will also be transferred, like when you travel by bus from one city to another. In reality, you "upload yourself," but that yourself is not you, but a copy of you. So, once the copy is done, you will still be in your original body, and the copy will "think" it is you, but it's not you. It's a copy of you! So, you continue to live in your body until you die, and, well, for you - that's it. You're dead. You're not living. You're finished. Everything is black. Void. Null. Done - unless you believe in the afterlife, so you'll be in heaven, hell, purgatory or whatever, but the point is, you're not longer on Earth "living forever." That's just some other entity who thinks it is you, but it's not you (again, because you're dead.)

This is represented by the parameters being passed by value (a copy) instead of by reference (same data) in the poster's image.