Well, origin and source of popularity are two different things. While most yeast-free methods of baking can be traced to Jewish roots, the bagel in it's current, cream-cheese dressed form was made popular (and for most intents "invented") in the US, in much the same way as the minced beef introduced to Hamburg in the 19th century by Russian sailors bears little similarity to the food that made McDonalds successful.

Not to mention the Doner Kebap you get in Germany vs the Turkish original.