My best read of this is that Lieberman is cashing in on deep resentment that the secular Israelis feel towards the religious Israelis who refuse the draft which is the norm in that country.
He thinks more of the religious folks should be forced into the military even though they feel religious obligations are more important.
The draft issue is just the most visible marker in the conflict between secular and ultra-religious Jews. The ultra-orthodox with their much higher birth rates have gone from a curiosity to I believe now 20% of Israel’s Jewish population. They account for half of Jerusalem’s population.