To deliberately drive nine seconds per lap slower than what you are capable of equally negates the essence of the sport.
I don't like it but it's not totally out of what F1 is. Sometimes, for strategic reasons, you go slower and one of those reasons is possibly to back other cars up. Hamilton played by the rules and I don't care a bit that he didn't obey Mercedes. I also understand team orders and I also don't like them.
So:
1. Team orders - I don't like but it is part of F1 since there is F1.
2. Driver going slower than possible for strategic reasons - I may or may not like it (depends on the reasons why that is being done) but I have no doubt that such a behaviour is part of the sport.
Elaborating on #2. It is clear in my mind that who really ruined Hamilton's game was Vettel. Think about it:
a) Rosberg was in no position to try an overtake on HAM because Ham's car wasn't slower, it was being driven "slowly" where a pass was impossible, and fast when such a thing wasn't possible. If anything they had equal pace on the fast sections.
b) Vettel had a faster car than ROS for the entire duration of the lap. So, what did Vettel do? Back off (just the strictly needed amount) , something he could do because Max was already out of DRS range, almost limping but keeping in touch because of Hamilton's tactic driving.
So you could argue that VET did the same that HAM did. And you would probably be right. He went slower.
Now, imagine Mr. Arrivabene, with his job on the line and a sniff at a victory, understood this, got on the comms and shouted: "OVERTAKE ROSBERG, THAT'S AN ORDER!"
Now, that would be interesting. And there you have it, Vettel going slower than possible because of his own agenda and preferences, who can deny him the right to do it?
In any case and all things considered, maybe even Vettel's help wasn't needed, Max was out of it so Rosbrerg would be third in any case.
The "problem" with a guy like Rosberg is that he apparently had his brain covered with german armour and his nervous system bathed in Finnish ice.