No, you really aren't a citizen unless you jump through hoops. The reason you don't see that is because you've existed as a citizen since birth on whatever citizen roll/database, with a citizenship link by virtue of your parents.

Maybe you get a free-pass as a baby/child/orphan. But as an adult, you don't get to just "appear" onto the electronic grid of citizen presence. If there were such a mechanism and it were easy and devoid of "loops" then illegal immigrants would have exploited it by now to become citizens.

You may think you're a citizen, but you are not unless you have the blessing of your government.