I can't really pinpoint an exact opinion about this subject because I'm still confused about it myself. But I do know that people have been debating about this topic for a long time, whether traced/copied art can be considered as art theft or not.
I had a couple of experiences myself with copied or repainted art here on DA. The first one was when some deviant took my Zuko drawing, and slapped on the text "GLEE" because he/she said his pose looks amusing, with his palm upfront and making an "L" shape, then he/she reposted it on his/her account. I was quite offended, because he/she didn't even ask permission, and was making fun of my drawing because of the weird pose. The second was when another deviant took my Percabeth painting, and repainted it sloppily on paint. A couple of my watchers notified me and DA or her took down the drawing not long after.
It's a different case if someone referenced off my art, or even traced it if it's only intended for practice, I'm fine with that. I also practiced drawing by tracing Manga comic books when I was a kid. But I don't think it's very appropriate to post your traced art online if you claim it as entirely yours (not giving any credit to the real owner). Tracing can be a very good way to start learning how to draw, even though referencing is better in my opinion, people has different ways to learn.
I don't really know DA's policy for traced art. Is it allowed?
Another thing is when someone copies off your art, but changes a couple of things, can that be considered as art theft or tracing? What are your thoughts?
Listening to: HP soundtrack
Reading: Harry Potter books
Watching: Iron Man 3
Playing: My iPad