The "campaign" is from the competition - many clubs who even had the courtesy to identify themselves in the CAS letter. The briefing referencing (incorrect) aspects of related party and similar matters is clearly, almost word for word, from those "sources". This is why the story is so similar in numerous media outlets.
Unfortunately, the journalists don't have the necessary understanding of the subject matter to either ask the right questions to their sources or get the articles technically correct. It isn't that complicated but it is technical. The most egregious misunderstanding was that the PL never has had related party rules. This is nonsense - the rules have always been there. It's just unfortunate for football that the international accounting standard measure used doesn't do the trick for our competition. So that competition are desperate to prevent another team competing for Europe. Remember the difference is at least £75m (probably more) to the bottom line (profit) of a club between qualifying for the CL and not. That £75m of profit is easily worth £1bn of value (probably more) if it can be "guaranteed" and recurring. So Liverpool, United, Spurs, Arsenal etc are going to fight bloody hard to make it hard for someone to make it harder for them. Its natural, its even fair enough. But the journalists really shouldn't allow themselves to be used.