I just don’t think it is that simple. I totally agree that if it was my kid i wouldn’t want them to fight in a war. And i think it is a little weird that they are taking kids instead of the parents, but it just isn’t that simple that taking the kids is just bad. The war could be going really badly and they really needed the soldiers. We just don’t know. And Rumple did murder the dark one when he was just a man and he did it without much thought either. He didn’t even worry about murdering him, he only seemed to worry about whether or not he wanted to control his power and his fear about that. When it came down to it he just stabbed the guy.
And i know that we in the present day who live somewhere fairly safe think about these things very differently and think about children very differently, but our now is not their then and it is just not that simple to say what Rumpel did was good or justified.