The Confederate Army drafted a year earlier than the Union Army and drafted a higher percentage of men into that army than the Union Army did. By wars end 89% of the Union Army were volunteers and 87% of the Confederate Army were volunteers.
Different dynamic for people defending their lands and their homes from a violent invasion by people trying to subjugate them.
Pressing men into service to defend the homeland is a necessity. Pressing men into service to go to a place that has done them no wrong and to kill people because their ruler tells them to do it, is not a necessity, and is in fact immoral.