Ben Levi: “I think the question is phrased wrong.
The real question is, Why are the Gedolei Yisroel opposed to the Draft?”
Answer: 1) The conscription of yeshiva students is opposed by almost all hareidi gedolim since learning Torah is more important than being a soldier, and learning Torah is the key to Jewish survival, especially in Eretz Yisrael. 2) The conscription of hareidim who are not learning full time is opposed by most gedolim since the army engages in systematic coercion aimed at forcing draftees to be substantially less frum in the hope that they will leave the hareidi community and become part of the mainstream of Israeli society – this leads to many hareidim who want to be baal ha-battim who probably would gladly serve if they felt the army welcomed them staying in yeshiva and working “under the table”. — 3) Anti-zionist gedolim oppose military service since the feel the medinah is treff, regardless of whether an individual is learning and regardless of accomodation of a Torah lifestyle.
These are three separate issues. Even if the army were glatt kosher (meaning all units were strictly Shomer Shabbos, strict in kashruth, no pritsus, no sexual harassment or sexual exploitation, no issues with immodest dress, etc.), and even if there were no shailohs about the halachic status of the medinah – the gedolim would want the professional students to learn full time. And as long as the medinah is not replaced by a Malchus Beis Dovid with a Sanhedrin with smicha and a Kohen Gadol with Urim V’Tumin to decide matters of war and peace- the anti-zionist gedolim will oppose army service.