There are a number of different reasons different people give as to why uploading is good.
For example, I do see making copies of myself as a good and positive goal. If there are two of me, all other things being equal, I am twice as well off -- regardless of whether or not I have any interaction with myselves. I am a really good thing and there should be more of me.
Some people, on the other hand, either subconsciously assume or actively desire a destructive upload -- they have one copy of themselves, the software copy, and that's all they want. The meat body is either trash to be disposed of or simply not considered.
Closely related, some people conceive of a unitary selfhood as a inherently valuable thing, but also want access to a meat body in some form. In this case, duplication/destruction is a problem to be solved -- the meat body might be disposed of, might be disposed of but DNA kept for potential reanimation, might be kept in cold storage... If we go by published science fiction, this seems to be the most common model. This is an interesting case in which the meat body (and perhaps the brain specifically) is often seen as a good and desirable thing, and in some cases the point of uploading is only that it is a useful way of insuring immortality (John Varley style transhumanism).
With so many mental models to choose from, it is not surprising that anyone who does not want to think about a lonely meatbody wasting away on a dying Earth just doesn't bother to consider the problem. It's an easy issue to ignore, when most people are still doubtful that uploading will be a possibility in their lifetime.
However, I think in most cases, people who think about uploading see it as "better than dying", while at the same time acknowledging your concern that really, someone called you is dying. Whether they see this as a personal death (as you do) or statistical death ("half of me's just died!") probably has no more ontological fact behind it than whether or not you have a soul... but of course, there are plenty of people who are willing to argue for hours on either of those points :-)
But's it's precisely this reference to "my meatbody" and "my computer body" or whatever that confuses me. When you upload, a new consciousness is created, right? You don't have two bodies, you just have a super-doppleganger. He can suffer while I don't, and vice versa. And he can die, and I'll go on living. And I can still die just as much as before, while the other goes on living. I don't understand what about this situation would make me okay with dying.
So I could understand it as valuable to someone for other reasons, but I don't understand its presentation as a life extension technology.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
Notes for future OT posters:
1. Please add the 'open_thread' tag.
2. Check if there is an active Open Thread before posting a new one. (Immediately before; refresh the list-of-threads page before posting.)
3. Open Threads should be posted in Discussion, and not Main.
4. Open Threads should start on Monday, and end on Sunday.