I've tried to take a balanced view of this and hoped there may be some for of innocent - or at least if not innocent, then more palatable - explanation as far as Yaya is concerned.
But as the tock keeps ticking, that's more and more difficult to do. As it stands, it's extremely difficult to see how Yaya himself has not been an absolute tosser in some way or another.
He must have known his agent was going to say this kind of stuff, and his agent obvious was told the birthday cake stories by Yaya in the first place. Yaya can see all the aggro its caused hence his first reconciliatory tweets.
And after the tosser of a manager ups the ante with further tweets and the most ridiculous SSN interview I think I have ever heard, Yaya says and does nothing.
He's either directly responsible for it, or deeply complicit in it. Either way, this is a HUGE lack of judgement on his part, that ultimately he is going to regret very very deeply.