Woah when did that happen! I had been using Twitch for some time. I left because there never was people who searched for music sets on Twitch. Never really got into trouble for streaming and uploading by them but they do incorporate a system which just plain mutes out most music recordings, that happened a lot. Never used or heard of Mix.
Youtube yeah people do search for music there, but in order to livestream they want an arm and a leg, the community is TERRIBLE, and the copyright trolls will take your sets down even though a live mix is not distribution of a product in the slightest, and rarely is it ever Profit.
I remember hearing about a lot of this, especially after universal bought soundcloud.