Being forced to risk your life for something you don’t believe in won’t create a feeling of unity.
So you don’t believe in freedom? Being forced by anyone to give your life for something is slavery.
I absolutely believe in freedom, but I see mandatory military service as a way of supporting the freedom for the rest of the population.
You do your service and hand it off to the next guy, you get skills and training, the country gets huge number of people who know the basics in a real situation.
There are also plenty of tasks in the military that does not require weapons or killing, in a disaster the services are used to support the civilian society, clearing roads, fighting fires, building temporary bridges, distributing water/food/shelter, providing emergency healthcare, setting up communications.
BTW, you use a very narrow definition of slavery.