Is flag such a goyishe idea? Shvatim had flags.
Flags themselves are not the issue (at the Chabad Lag B’Omer parade, there was usually an American flag, Tzivos Hashem flag and Mesibos Shabbos flag).
The zionist flag however was made specifically as part of a general movement to create a secular brand of Judaism, the flag is part of the symbols that we can be ככל הגויים ch”v.
Now we have a group of American Jews who want to tell Israel how it should be run.
It is the obligation of every Jew, especially a majorly influential Jew, to do everything in his or her power to ensure the spiritual safety and physical safety of the Jewish people anywhere in the world, especially in Eretz Yisroel which is every Jew’s homeland.