Presumably he was promised they'd begin building a team to compete further up the league with him at the centre of it. Then one week later they go and flog their star striker to a league rival. He must have looked around at training and thought 'do I want to be in a relegation scrap or double my money and play in the Champions League?'
Given, Vlaar, Delph, Cleverley and Benteke. That's the spine of their team gone. Got to be looking at relegation next season as it stands.
It still isn't right how he's gone about it but I think its slightly understandable where he's coming from. He was crazy to turn them down the first time. He'll get all the abuse he deserves though.