"Open borders for Israel" is a belief common among white supremacists that American Jews are hypocritically demanding a pure Jewish ethnostate in Israel.

ADL

https://extremismterms.adl.org/glossary/open-borders-israel

Meir Kahane...

American-born Israeli Orthodox ordained rabbi...

... "The question is as follows: if the Arabs settle among us and make enough children to become a majority, will Israel continue to be a Jewish state? Do we have to accept that the Arab majority will decide?"

https://en.wikipedia.org/wiki/Meir_Kahane#Ideology