Lernt: The Zionists know as well as anyone else that a volunteer army, like the US Army, is much better than a forcibly/unwanted drafted enlistees. But the Zionists built their army to first, and foremost, be a “melting pot” to turn all recruits into Zionist ideology subscribers, including secularization more than anything else.
If they don’t forcibly draft, many non-Zionists will remain non-Zionists. And nothing can be worse than that, from the Zionist government’s perspective.