I didn't get the impression it was an American Gods-type thing. It seemed more of an immigration type thing. Ash wants to go to America to go to America, not because there's a pull that, in an American Gods sense, the Gods come along with the immigrants as a natural consequence of immigration; they bring their Gods with them along with the rest of their culture.

I don't know if you read Angels when it was still on tumblr; I didn't manage to read the whole thing before it was taken down, but one of the plot points was that Ash has a brother already in the US, which adds even more to the whole Jewish immigration plotline, as families come piecemeal, rarely all at once.

So I don't think it's a situation of "send European angels to protect the Jews in America", I think it's much more "these European angels come to America to protect one specific Jew, who they have known since birth; the demon wants to come because he's getting very antsy about pogroms".