Well, if you duplicate an apple (or even another person) there is never any confusion of which one is "real". They are both identical duplicates.

However, when you talk about duplicating yourself, all these smart people are suddenly wondering which "self" they would subjectively experience being inside. And that's pretty ridiculous.

So you need to point out that the self doesn't really exist over time in the strictest technical sense, in order to make people stop wondering which identical copy of their subjective "self" will end up in.

These questions don't make sense because In the same way that you can't subjectively experience other people, you can't subjectively experience yourself from the past or the future.