Viacom Breaks Usual Code of Silence Over Mergers

Viacom is opposing the Comcast/NBC merger. They are particularly worried about the future of over the top video.
http://fjallfoss.fcc.gov/ecfs/document/view?id=7020924474

Why? Not why are they concerned, that is obvious. But what has scared them so badly that they have have broken the usual industry code of silence?