A haven that frum jews all over the world are petrified of being citizens of, or their kids being citizens of, because they will be forced into an army which tries to force them to break halacha.
Whose Halacha? The Hesder Yeshivos seem to have no problem with the army.
Yes, the Museum (to use the term of Rav Aryeh Levin) of Charadim will not survive the army, and neither will those who expected to live in a museum/ghetto. Your “American” friends just don’t want to be Dati Leumi or Chardal, and feel the need to identify with the Charaidim. As such, they can not join the army. (Or, they are simply scared).