The media's job isn't to filter anything, and when they do, it is agenda driven.
An ambassador's job isn't to negotiate in spite of the president. An ambassador's job is to serve as an envoy to the president.
I think this is an area of clear difference of opinion. I think the press/journalism - if not the media writ large - do have as a part of their job to provide context and background. I think that's key part of journalism. I accept the criticism that it is frequently done poorly and I understand if you're on the right you might feel there is constant bias and belittling of your positions by the press - something I think Scott Spicer stated affectingly in his 2nd press conference. But I just don't see journalism as being done responsibly when you just say 'here's what person X said, here's what person Y said - good luck figuring it out.'
Similarly I think ambassadors and the state department at large frequently have a complicated task when it comes to negotiation and relations. Frequently embassies have to keep back-channels and communications separate or adjacent to other public communications. The President similarly needs the ability to have a public face on some issues and at least some measure of private assurances. I get that the line on where that becomes obfuscation and dishonesty can be tricky - but I still think it's necessary. I'd point to something like the Cuban missile crisis as a well documented scenario where public vs private communication, intentional and unintentional signals were critically important.
As an aside but still germane I think that's one of the reasons Manning's betrayal of his country and the IC was so damaging and unforgiveable in my view. His disclosure of state department communiques made that private communication senior leaders rely on to make decisions and communicate privately public - inflicting significant harm on diplomatic efforts worldwide. Further, from that point on those communications were moved from the secret level (and systems) to the top secret level (and systems) greatly reducing the access of battlefield commanders and decision-makers to state department insights and efforts. It's of course an exaggeration to put the majority of the disconnect between state dept efforts and the military on Manning but that douche definitely contributed - and that does cost lives.