The correct answer is that the Frum Yidden should protect Klal Yisroel by learning Torah while Chilonim should do so by joining the Army.
Klal Yisroel needs a strong amount of Limud Torah. The Chilonim are completely neglecting that. So the responsibility of Limud Torah is falling fully on the shoulders of the Frum Yidden. Therefore the Frum should learn Torah while the frei go to the Army.