I'm not defending poor service standards, but I detest people who think that "their money is very big".
If he's not happy with her service, give her a telling off, or go and tell her supervisor, or refuse to patronize the stall again.
He may claim that he didn't want to get her into trouble, but I don't buy that.
His objective was to humiliate her because he thought that "his money was very big".
The report doesn't state that the coffee lady was a prc national, but that's not relevant. If her service was poor, she could have been from Timbaktu for all we care.
Similarly, the customer could be a billionaire, it doesn't change his deplorable behaviour.