Kos is different from Williams

Because Williams took government money. Even if Kos was spreading message for the Dean campaign, everyone who financially contributed to this propaganda campaign would have agreed with its message. On the other hand, government is (theoretically) unique in our society in its ability to coerce payment from people. In effect, government propaganda takes away our first amendment rights by forcing us to support messages we do not agree with. That is why Williams was wrong for being a party to this violation of the first amendment. It was a violation of civic ethics, if not journalistic ethics, and Kos has nothing to apologize for.