Moss has been on McCarthy's staff the entirety of the time McCarthy was in Green Bay. On the org chart Moss was higher than anyone else on staff, including all the coordinators. Moss did more administrative work for McCarthy than anyone else. He was also McCarthy's closest friend on staff.
This is McCarthy getting his thoughts out through Moss. With this along with the James Jones comments and Jeff Saturday it's pretty clear Rodgers and McCarthy had some serious issues, going back to 2011 or so and it eventually rotted to the point where this had to happen. That's a long time for the QB to be rolling his eyes at play calls and indicating that he thinks the calls are "f@#$ing stupid."
Veterans can deal with that. Younger guys don't as well. Once the Packers roster turned over like it has in the last 2 years the issues became more raw and had to be dealt with.
Moss will get a job the same day McCarthy does.