Health,
On a previous thread I listed the Mizrachi Gedolim that held that there is a chiyuv to participate in the army, chiyuvis not just kiyumis. Maybe we understand the word chiyuv differently.
More importantly, as I wrote above, I don’t mean that someone should be forced at gunpoint into the army. They should be drafted and have to come down for an interview. If they claim that they hold it is assur on the grounds that the entire Medinah is treif and being in the army is an assur of hischabrus, then they will receive a patur, but they will also be ineligible for any financial assistance from the treifene medinah.