I think it can be material for class at times, I've seen it assigned for some college course in the US at least. Even if it was actually found in a kid's bedroom with notes that doesn't mean they are some kinda nazi. Like is there no Israeli citizen that owns a copy of Mein Kampf? If one was serious about being anti-fascist it seems like a good thing to study. Israel has a weird definition of 'child' in their propaganda so who knows, was it a college or high school-aged student's room?