Team thing I understand, by why then did Bottas think they were going to change back? If a re-swap wasn't part of the strategy plan then why the radio message saying they weren't re-swapping and that they'd talk later and explain? That (to me) sounds very much like a change of plan that HADN'T been part of the original discussion!
Toto Wolfe explains in detail on the BBC F1 website, Due to the pit mix up which Wolfe takes full responsibility for, Lewis ended up behind Vettel and blistered his tyre getting passed him. Vettel said himself that Mercedes made the right call!
Why would a team give back first place to a driver that had no hope of winning the championship to the driver that was on the brink of securing another world title for Mercedes ? It makes perfect sense to me and like I said, if any other team in the same position did it I would have certainly accepted it...I doubt very much if Lewis wanted to win that way, in fact he's said he feels awful about it.
As for Bottas, he needs to get his finger out... lets be honest he has been disappointment I had great hopes for him at the beginning, shame he's not taken advantage of being in one of the best cars in F1, in fact I am at a loss as to why they have kept him on personally.