YouTube's Fuck Up

I have a question I'm sure anyone can answer.
You know when you upload a music video you'll get a notice from YouTube about copyright and all that jazz and they will basically do this to your video (circled in red).

So, the question at hand is why does music videos get a copyright notice yet people who post mp3's in a video with a single image don't get one?
You can't go after one without going after the other, now. I mean, am I wrong for thinking this?