Without some absolutely top-tier propaganda, you'll end up with a whole load of conscientious objectors who'll have to be cajoled or outright threatened to fight.
And you don't want to give a gun to someone who's been forced into a miserable situation they don't want to be in with no way out.
On the other hand, maybe there are enough zoomers who'd take to conscription like their (great-)great-grandparents did in the 1940s. Gung-ho, fight the enemy, come back with PTSD if you come back at all and all that.
Maybe they'll leave that last part out of the propaganda. Or maybe this time they'll promise (pretty promise with sugar and a cherry on top) that since we have PTSD treatments now, those will definitely be implemented for those who make it back. Absolutely. No question.
Yay war!