YY > I did not claim that Mizrachi ITSELF made their children non-religious. It facilitated contact between virulently anti-religious people on one hand, who the secular Zionists undeniably were, and people who were basically ehrlicher Yidden who they could never reach on their own.
Eastern European Jews lived separately from Reform Jews in mid 19th century, and some rabonim blamed Mendelssohn for translating chumash into High German, enabling Jews to read German in general. But in the early 20th century, various -isms were all over Eastern Europe. There were no Meah Shearim, everybody could read newspapers. They were in Yiddish and in Hebrew and in Polish and in Russian. I think you are projecting current charedi community into 1920s and think Mizrahi went there.
The modern movements were very attractive: “we can build a new life!” If you and I were there, we would probably join also. So, under these conditions, Zionism in general was a good thing comparing to the alternatives – taking people with socialist (left wing) or nationalist (right wing) ideas into building up Jewish nation instead of Russian/Polish/German or world communism. And, of course, religious Zionism let people combine these new passions with traditional Judaism. I would say even if/where they went too far (from our view a century later),