Do you not know about the context? The admin threatened to block the deal because Trump didn't like CNN's coverage of himself. Neither side is all that great here. Even if the DOJ lawyers wanted to pursue it for the right reasons, Trump and by extension Sessions let it go through because of his animosity towards CNN.
This was probably the most frustrating part of this entire process- they had so many other arguments they could have pulled out of a bag and instead CNN was the one issue that the executive branch had?
It sounds like this issue rallied AT&T / Time Warner's legal team as well. Per the article, it sounded like AT&T / Time Warner used this "issue" to demonstration that the DOJ was opposing the merger not due to any logical reason, but out of spite.
