FB needing copyright laws for a song I posted?

So I recently posted a collage of photos (a video clip) with some music in the background. Then FB put me through a series of questions asking if I had copy rights to the song? Lol wth?!?!

Has anyone else experienced this? Is this serious or does FB do this to cover their end if there ever are lawsuits? Should I be concerned that I have music playing in the background to photos?

I am not claiming it's my music nor am I making money off the music...