Racism? Actually, it's about the "behaviour", not the "race". At 2:01 she says: "My ancestors are also from China, but my manner is not like this. Didn't their parents teach them how to behave?". The subtitle in this video are not 100% accurate but you can ask any Thai-speaker to confirm my message.
And regarding the economic contribution, you may be interested in googling about "zero-dollar tours". Large amount of money spent by Chinese tourists does not enter our economy at all. This is also irrelevant. Such contribution(?) does not equal to 'so I have my all rights to do anything I want'.
It's not only the matter of economy or money, you know? There is also tradition, social value, order, history, etc which do not have monetary value. Money is not everything