If the situation became an emergency then MAN has stated that it will accept them.
Roverman, I'm not sure this is a generous concession by MAN, so much as an obligation, or possibly even a legal requirement as I think someone once suggested, to accept an emergency.
However, your two points are well made. It was interesting that no flight declared a fuel emergency to come to MAN and as the fog was well forecast on this occasion, aircraft probably carried maximum fuel anyway.
The situation you mention with regard to contracts I've no doubt is correct. Excuse my ignorance but does AOC stand for 'Airline Operator Committee' and is the airport represented in some way? Although the (aviation) contractual relationship is between airline and handling agent, doesn't the airport have some input if the agents are preventing the airport from functioning as it should? I assume that the agent is a tenant of the airport paying for space and any services provided under a separate contract with them. It could be a messy triangle but there must be some coordinating committee to resolve issues, isn't there?
Please, can we stop mentioning the KLM MD-11? Yes, it was a mess to learn from but it came in as I recall just as we got some heavy snow. And wasn't it the following winter that MAN did things much better and got some good publicity?
I do get the impression that the airport now relies more heavily on what the handling agents advise in making a decision compared to years ago. While this may seem reasonable, if the agents are continually saying they can't guarantee handling diversions satisfactorily, MAN must surely challenge that and demand to know why.