Here’s my personal opinion; people should learn torah as much as possible. Yeshiva bochurim and young married people should stay in yeshiva and learn.
That being said, I don’t know how to explain to a non-observant Jew that they should fight a war and let the chareidim learn. Our learning is as important as them risking their lives in a war?? You can explain that?? Our learning guards them so that they come back alive? Do they believe that if they don’t even keep Shabbos?