The guy is simply and purely a football mercenary
I'm not sure that's fair.
Bale's always struck me as a pretty airy, happy-go-lucky kinda guy, very different from the sort of driven psychos that succeed in top level sport.
Harry Redknapp's Tottenham was the perfect environment for a personality like that to flourish and grow, and once he got on top he thought playing for the biggest club in the world seemed like a cool adventure, so off he went.
And it went pretty well! He's a top player. But eventually a situation full of dominant personalities just kinda ate him up. He was just never the kind of person to be the galvanizing central figure and leader for a global sporting institution on and off the pitch.
I'm sure he's pissed off and feels wronged by Zidane, and he's not going to take a massive pay cut to help out the parties he blames for his problems, but more than anything I think he just wants to play regular football in an environment where everybody likes him again. China offers him that.