Because this is a site for Art and people fills it up with screenshots, which does not belong here. Did you read the copyright policy on here? It's rules that you cannot upload anyone else's works onto dA without their consent.
I read it but it only make sense if he/she has stole this. If seen many pictures like this and no one of them have been banned. Moreover, I only wanted to know, I didn't mean to offend you. Is just that I didn't understand your comment
Well, that's because it takes a while for the staff to get to newly pictures, and if you post something, most of the time it will probably just disappear in a bunch of artworks in the system. I have a lot of friends that have gotten their stuff removed, and I don't know HOW you can get it to only mean art theft, it it's about any material at all.
when you submit anything to your account on dA you agrees with the TOS and that means that this image is produced by you, so if you submit anything else, that was not produced by you, or is creative commons, then you are violating the Copyright Policy, because most things are Copyrighted. Movies on TV, Anime, Cartoons, comics, games, photos, photos on google etc.