The human brain is really good at keeping two conflicting ideals "harmonized". I don't think it's much of a stretch to fall to the romanization of the military while also recognizing the killing part of it.
It's easy to fall to propaganda. Is it the recipients fault? Is it the sender of propagandas fault?
I would argue both to some degree, but mostly I will blame the sender because they are generally older and better at rational thinking when compared to younger people. (I'm grossly generalizing here. I know younger people who can think more critically than some older generations).
Summary: by the time they realize they don't want to be part of it, it's too late and they have to serve their time.
No. I don't that would be a good solution. Maybe create a law that the military has to give informed information. The intention would be to prevent propaganda in the first place. Then age or wisdom would be less impactful because education on the horrors of war would be more universal.