how is this image considered mature or full nudity?

http://www.apollogt.com/AMM30LL.jpg

A crumb of context, perhaps?

Who did the evil labeling?

Why does it matter?

"Mature" is now the default setting for all images.  You have to manually change them for images where that isn't the case.

I have no idea if that has any bearing as to what happened in your case or not, as you didn't provide any details...