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Reading the lawyer's response, he's doing exactly the sort of hyper-vetting that reporters endure whenever they write a story that makes a newspaper editor nervous.
Basically, he's trying to check the boxes.
Defamatory accusations? Check (saying someone broke the law).
Conviction or verdict in favor of accusations? No check, therefore no accusation publicized.
This is absolutely routine legalistic practice whenever news management encounters something it wishes to avoid publicizing whether it's fearful of defending itself in a defamation lawsuit or whether it's just trying to wear down an enterprising reporter whose stories disrupt the publisher's lunch table options at Rotary.
Basically, the Comcast lawyer is exploiting journalistic conventions to keep this ad off the air. But ... every single news executive I've ever worked for would find the rationalization acceptable and has probably exploited the conventions as well to kill or dilute a solid story on behalf of management.