User blog comment:Yumiko the Kitsune/Why would Ubisoft delete 10 years of footage from the 3 biggest Just Dance channels?/@comment-34325402-20190820085347

Probably Copyright concerns.

Just Dance gameplays have Copyrighted music, which can cause a Copyright strike which will obviously target the YouTuber in question, but If the gameplay recorded has a song of which Ubisoft no longer has rights to, then Ubisoft could potentially be targeted by Copyright too. Or that's my theory, anyways.