What the Haredim are afraid of is the influence of living cheek and jowl with irreligious Israelis - male
& female - for
three years - irreligious meaning they don't believe in Torah or G-d,
keep nothing, know nothing: not shabbos, not tefillah, not Tefillin, not kashrus, not brochos, no Torah study - practice pritzus and ridicule, will forceably cut off your peyos etc etc. I also wouldn't be too happy!
Those Haredim who entered frum in the 50s and 60s almost invariably not only came out un-Frum - they came out virulently
ANTI-Frum! Even an idealistic chilloni Zionist, after 3 years in Zahal, will emerge a anti-Jewish and a non-Zionist and flee to New York & California. with an enduring bitter bitter hate for the Israeli system!
The solution is
all-Frum units like Netzach Yehuda batallion.
As for conscription of Haredi girls in to the army: the Chazon Ish told Ben Gurion in 1951 that the Haredi world would rather
martyr itself to death rather than see its virginal daughters sexually ravished by rampant
lothario lecherous profligate Israeli secularist Zahal officers! Ben Gurion saw that the Chazon Ish really meant it and backed off. Had Haredi girls been conscripted in 1951, the Haredi would have become totally extinct today: the deleterious effects of 3 years in Zahal is
that bad!
When a Haredi really believes that he's on a Mission from G-d and doing a Kiddush Hashem, he is eminently capable of dying for his beliefs - a Jewish
shaheed - and I think soon there will be some bloodshed and Haredi deaths.