By the same logic it was taken from them by right of conquest, as their ancestors did to others.
At some point the state recognizes property, even if it was seized or granted, say, 450 years ago. After that you cannot take it without compensation.
It's one of the basic principles of most ownership law that after a certain time if you don't complain about people violating your rights as an owner for long enough, you lose them. This is the case for trademarks for example, or for real estate in many places (New York is an example). These concepts of usucaption/adverse possession go back to roman ages.
What about the British crown jewels which originated form India?
IIRC Pakistan had claimed them too
If it was, they should have cared about it earlier. Right after the borders opened...Now, after lots of stuff was reconstructed and supported with tax money, they come back....
It is not theirs and never was. There is no such thing as a “legitimate king.”
And I'd argue that historically, the nobility were stewards of the state. Since they no longer fulfill that function, the property should remain with the state.
Not that I have much sympathy for those folks, but what does their (il)legitimacy as nobility have to do with their right to own property and possessions? There are solid arguments against their claims, but this isn't one of them.
According to the article the property in question was legitimized as private property by German state after abdication. So after 1926 the formerly royal family were just rich normal citizens, and the legitimacy of their former royalty should not matter.