Since the first messages from users regarding problems with links to Filmmusic.io already came to me a few weeks ago and this has increased massively today, I have now instructed a media lawyer to write to Youtube and ask them to refrain from this "business-damaging behavior". The costs will amount to about 200-300 euros for me for the time being.
I'll probably never see the money again, but I don't think big companies like Youtube treat us users like test objects in a big experimental box. Therefore, I could not reconcile it with my conscience to simply accept such behavior on the part of Youtube.