The simplest explanation for all of this is that Button ignored team strategy. I would not use the word team orders, because that would involve orchestrating a change of position. Team orders usually lead to a restructuring of the positioning of the drivers, by slowing the leading driver. On the other hand it could be preventing an inevitable change of position by slowing the gaining driver.
In order for it to be team orders in this situation, Button would have to inevitably overtake Hamilton, and the team would have to hold him back by telling a target lap. There is no evidence to suggest Button had more fuel or that his tyres were better and he was running so much faster that He would pass lewis.
In fact looking at how Lewis turned on the pace after he retook the position, i am inclined to believe he had more fuel. I have not seen this mentioned, but believe or not, following behind the redbulls as well would also save fuel. The dirty air wont save the tyres, but it reduces drag which means fuel would be saved.
In this case, Button was nowhere near catching Hamilton had it not been for the save fuel command. Some are made to believe Button would eventually get Hamilton, no evidence there.
If there was no save fuel conversation then the race would have finished with no drama, Hamilton driving away from Button and Button trying to keep up.
The idea that Hamilton made a mistake is just as unfounded as the idea that Button was not told a target time.
He was told according to Goss, and indications are that he ignored. But that is all good still, Button had all rights to have a go, as dishonorable as it is.
He noticed Hamilton was closing in on a 21 point deficit, and was gaining large chunks of points every race. He desperately wanted to maintain a gap to Hamilton because going by the trends Hamilton will surpass him on points and then move off into the distance forcing the team to support the boss for the WDC.
Button was thinking of the big picture when he made that sneaky move. It was all worth it to him, looking on the scheme of things.
Any how you look at it, mis-communication (yeah, right) or Button took things into his own hands (as his fans were proud of in races like Australia, Malaysia and china; so i am more inclined to believe this one) he consciously made a decision to take advantage of what seems to be a slowing hamilton, which is not something he sees every race and it would be easy pickings to add a 7 point gap.
So yes he was justified, but it was dishonorable and says something about his willingness to play the team game.
I will stay away from the argument that the team slowed Lewis for button to pass him, so he would lead the championship and the team would lead the championship. It's perfectly logical looking at the standings, but it's a very big risk sticking the move with so many laps left, and it would indicate Whitmarsh would be favouring Button this early in the season.