Again, a perfect argument against cross-media ownership. A broadcast company should not be able to own a print company so that these types of conflicts of interest couldn't happen.
Is it a conflict of interest? Yes. But there's no need to regulate this or say, "This type of thing should not be allowed." The market has worked. The news is out that CNET had selected the Hopper with Sling as best in show. The news is also out that CBS interfered with that decision. People will now look skeptically at CNET (and, I hope, CBS's other news products as well) in the future. That skepticism essentially kills CNET's credibility, which will ultimately destroy any media company. The free market will destroy a company for its abuse of power, and there's no need for a government entity to step in.
At this point, the only thing I think CBS can do to restore credibility is to publicly apologize to Dish and CNET employees and sign a public pledge to never interfere again. They'd still have a black eye, but over time it could heal. Right now, they have a gushing, mortal wound.
Where this would have been a problem is if CBS had managed to do all of this on the hush-hush, and we would never have found out about it. But right now, Dish has some marketing fodder: "You have to see the new Hopper - it's so good, even CBS doesn't want you to know about it!" The perfect message for the rebel-minded American viewer.
However, I don't think there has to be an inherent conflict-of-interest for ownership of media companies. It is entirely possible to have a stone wall between marketing and editing. But I also think the reality is that we all have to maintain a certain skepticism of all news outlets, whether they have a conflict-of-interest or not.