If they die in the battlefield, what then? More uncaring, apathetic teachers and nurses might replace them, and that would just make the students' lives worse. Their hands are tied and there is not much they could do, which might change later in the story idk.
Again, I would suggest watching the anime because it does a much better job at this. In the anime it's very clear that they blame themselves for every death that we see.
This is the Nuremberg defense. "I was just a cog, I couldn't do anything else, someone else would have done the same."
Meanwhile the system keeps working because people like them keep supporting it. I'm honestly quite surprised people who be so defensive of those who participate in turning children into soldiers, when those characters show no resistance or attempt to change course.
thef1shhasturnd is absolutely right - I already have strong opinions and those teachers and I can guarantee you watching the anime wouldn't change it. I'm also amused that you think "watch it, it would give you a better opinion of people who train child soldiers" is something that would sell me on the show.
I do agree with you that the anime does a way better job at showing how the teachers are affected by the war that isn't just them sending the kids to the warfront while they drink tea and strategize. Furthermore, there is just so much we still do not know about the war itself or the "grimoire" and why magical children seem to the be temporary answer to the war at the moment.
Seeing Omi's reaction to the death of Laura really changed how I viewed her relationship amongst the students. Fran for me seems very on par with what we see in the manga but more direct with her presence among the children, at least for me that's how I see Fran in the anime compared to the manga (in a very general sense).
Again, what do they do about it ? Have they taken a single action to stop children being sent to the battlefield except send even more children to the battlefield ? I'll say it again. If her defense is : "I trained child soldiers, I sent child soldiers to the battlefield, one of them die, now I feel sad"... Then I don't think feeling sad absolves you of your participation.
And even if "someone else would have taken their place if they didn't do it", in the end, I hope someone will come out and condemn the use of child soldiers, and punish those who participated in that violations of human rights. And I don't mean it as some gruesome display of revenge. Prison would be fitting.
But for the love of the goddess, don't tell me "feeling sad about a crime I willingly helped with" absolves them of their crimes. It doesn't.
Now, maybe they actually
could redeem themselves, at least partly ! If eventually they
do something instead of just feeling sad of the thing they're complicit to, they might earn some credit back ! While so far they have shown no sign of it, they could either be acting undercover, or simply change their mind later, hopefully when it's neither too little nor too late.