The only Celtic nationalism that I am aware of was growing up on the Asterix and Obelix cartoons as a kid. The founding of Israel was primarily motivated by the events of the Holocaust and Jewish persecution in Europe. Technically speaking, it was not that different than what drove the Kurds to form Kurdistan or the Armenians to form Armenia. In other words, it is not that uncommon for persecuted minorities to want to form nations that can protect them. And on the other side of the fence, Arab nationalism was hardly an inclusive and religiously tolerant movement either. Over half of Israeli Jews are Sephardic - so are in fact Semitic Arabs - just not Islamic. Like most things, this situation is tragic.