A simple explanation is that many of the people making decisions at YouTube can't tell their glutes from a hole in the ground.
An engineering explanation is that they're doing adaptive control on their content management system but changing the parametrization of the feedback controller with a frequency too close to the dominant frequency of the outside drivers of the controlled system. As we know, this leads to all sorts of chaotic behaviors, instability and strange attractors.
No. I think it's more likely that many of the people at YouTube don't know what they're doing.