There are lots of reason, they are under 18 or they have written spam hubs or they have violated the rules in other ways.
Maybe he had violated some rules such as creating a hub with an adult content, copied articles from other site or just chose to unpublish their hub. Another thing also is that the age, below 18 is actually not allowed on the site.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.