"I will bless those who bless you and curse those who curse you" is a statement of fact, but Genesis 12:3 isn't a source verse for any of the seven commandments for Gentiles. It seems to me that Gentiles are obligated to support the Jews indirectly by obeying the Jewish God and not living in Israel where we don't belong.
I don't see any obligation that I know of. It's more like there's no obligation to pick up diamonds off of the floor though, and to complete the example, while a thief who will use the money to kill you is following behind. You get benefit if you do it and a major negative for doing the opposite, and like it's not really possible to honestly say you don't care.
Obeying the "Jewish" G-d doesn't mean you have to support Jews. Also, Noachides are encouraged to live in Israel as non-citizens, who can nevertheless have entire villages for them, like the Gibeonite villages.