I recently found out that you can offer your own site material for Duolingo articles, and I wanted to volunteer my site 120Paws.
It said I could not because it contains offensive material.
It is a blog that follows the lives of six puppies from day one through their trials and tribulations as they learn about the world.
I don't understand how it's offensive.
The message said it MAY contain offensive material I believe - that's happened to me before, and I think they just have a filter that grades the previous content, and maybe if it's possible that there could appear offensive content, it will block it. The same thing happened to me with a celebrity review piece I tried to put up, and even one about dieting. It's got to be some kind of computer filter that picked up a red flag from somewhere in the site. Maybe even just the category blogs is what's blocking yours - who knows!