My 8-Bit Cover of Jacques Offenbach's Infernal Galop, more often known just as the Can-Can.

While uploading this cover to youtube, I was hit in the face with a content ID claim. Does some greedy companies somehow actually own the rights to the melody, which, by every source I found, is and has been public domain and free to use for decades by even the most strict laws of every country on this earth, or are they just scamming me? Especially when they claimed only a part of the music.

Edit: the content ID claim has been cancelled :)