Yo – it’s a very fair question to ask why ashkenazim had a Holocaust and sefardim (mostly) didn’t. The answer is that Hashem doesn’t bring a Holocaust because of ignorance. Ashkenazim, who learned more and knew better, went off and fought against Hashem. Sefardim never did. It doesn’t mean that it’s ok to be ignorant.
1 – I never said that some communities don’t need co ed schools, but as you said, they’re for people who are at risk of intermarriage. The Syrian community was in danger of (and was actually) intermarrying; they were not knowledgeable and were not very observant. Boruch Hashem that changed, and now they have a robust Torah community, no different than the ashkenazi yeshivos.