Same! I wonder how they hold up now that I'm an adult. I used to read anything war-related I could get my hands on as a child, including Brian Jacques' books.
Oorlogswinter didn't leave much of an impression on me when I read it way back when. The plot Imma described didn't really ring a bell even though I've read the book. A few children's books that I do remember were Thea Beckman Hundred Years' War trilogy (Flemish runaway girl and later her offspring get caught up in the horrors of a bloody medieval war between England and France) and Boris by Jaap ter Haar, about a 12-year-old living through the siege of Leningrad in World War II. I think these were written for children of about ten years old and up, so arguably not quite little children, but still.
I read all of those, too! I think I've read almost every book by Thea Beckman and own most. I was a frugal girl even as a kid, I would spend my pocketmoney buying the books the library no longer wanted (at 1 Dutch guilder each.... that was a long time ago!). I own Boris too, it didn't appeal to me at the time, the reading level printed on the cover is AVI-7 which is indeed for kids around 10 years old. Most of Thea Beckman's books were a bit more complicated but I remember reading those in primary school, not in secondary school. I stopped reading children's novels around the time I went to secondary school.
Another favourite at the time was Evert Hartman, who among others wrote a novel from the perspective of a teenager from a nazi-supporting family and also a book about a primary school class being taken hostage by terrorists (which is a thing that happened here a couple of years before that book was written).
American kids would benefit from reading some of those books just for the historical context. I have always enjoyed reading about history. I was close to my grandfather during my middle school years and he had participated in WWII. I wanted to understand the war so I was reading about it in middle school. What eluded me for a long time was WHY people sided with the Nazis and against the Jews. Heck, I'm still working on that somewhat. The books I read just weren't giving the cultural background I wanted.
Sounds like the books you mentioned might have provided some of that context.
Yes, they would have provided that context! And some of them have probably been translated into English as well.
For me, it was never very hard to imagine why people sided with the nazi's. My grandparents lived through that time as well and I was close to them. We talked a lot about WWII. You have to keep in mind that in the 30s, the whole world was in deep economic trouble. It was way worse than what we were going through now and the governments were failing harder than our current ones. Most countries had thriving nazi parties / movements, it wasn't just a thing in Germany. It's hard to believe now but nazi's were considered cool and intellectual in those days - the uniforms, the songs, the radical new ideas and science (it's hard to imagine now but eugenics was seen as modern science in those days). It was a meritocratic organization, a hardworking lower class man could rise up through the ranks within the party. In my country they gained quite some support among mostly the lower middle classes and farmers. Antisemitism wasn't their main selling point at that time - even though the leaders of the party of course had always been deeply antisemitic, that wasn't true for all of their supporters. They had no idea about the Holocaust. They wanted Volkswagens and cool clothes with skulls on them.
When Germany eventually invaded in 1940, the first period wasn't that bad. The Germans saw the Dutch as their racial equals and treated us quite nicely. For many people, the occupation at first was little more than a change of government and they sort of tolerated the nazi's. Many people didn't really agree with the deportation of Jews, but thought "well, what can you do about it?". And it was dangerous to speak out. One of my grandparents, their family never supported the nazi's, but they shared a house with a family who were active Party members (their sons all died in Russia) so they couldn't speak out. One of my other grandparents was a fairly passive member of the resistance - they allowed some people to hide on their farm, it was arranged by a cousin who was eventually killed for their resistance membership. The third grandparent ran a soup kitchen - the soup kitchen provided much needed food to the inhabitants but it was paid for by the German occupiers. Were they collaborating by accepting a job that was paid for by Germans? Perhaps, but otherwise a lot of people might have starved. None of them supported the nazi's but as you can see they all handled the situation differently.