Germany gives its citizens a choice. If they want their foreign-born/foreign-resident children to be German like their parents they can register them with the German government within their first year. They do not have to register them. If being German is not important then they will not register them. Anyone with strong ties to Germany is going to want to register their children right away. I can't say that's how I would do it or how it should be done, but the policy seems quite straightforward and well thought out. The registration burden is not onerous, and the time limit is reasonably long.