“This was the approach of the gedolim in Europe.”
to compare Europe to America is irreverent for most of Europen Jewish history we lived under monarchies, and even when under parliaments we were not dealing with any legislation that effected any 7 mitzvos that we could have possibly chained with out causing a massacre worse than the Holocaust. Jews in Europe were also in parliament system so anything we would do would be seen with extra suspicion, remember Agudah was a real legal political party in Poland like in Israel, and those who opposed it thought it would cause eivah. To compare America to Europe is like comparing a hatzlah member working Shabbos to a banker
PS: It’s known that the Chofitz Chaim tried to start a 7 mitzvos campaign in Europe.