This discussion should separate theology from sociology. I see a list of MO problems to include girls learning Gemora and inappropriate tzniut and keeping shabbos. Are you suggesting, like R Eliezer, that these problems are connected – that girls find tirutzim in Gemora to go dancing in Shabbos? I don’t think so.
Maybe confusing issue is putting everyone who is lacking observance into “MO”. MO schools invite both families looking for “MO” experience for kids and those who simply want to send kids to a posh Jewish school. This is both negative experience for the kids from the first group and hopefully positive experience for the latter.
So, to see the effect of the school you should not simply point to graduates and see how they behave but compare students before and after they go to the school. This is now a recognized metric in education evaluating teachers and schools. Maybe someone with more knowledge about these schools can provide their observations.