Racism helps too. Some Indians are seen as white enough. Actual Asians will never be seen as white.
I highly doubt it's racism. I am of course not defending, in any sense, the fundamentally racist and toxic AngSax culture / socio-economic model.
I believe the difference in traditional culture plays an important role.
The subcontinent has been ruled by ethnic and racial minorities for millennia, and the go to ruling strategy involves physically impoverishing and weakening the ruled majority, and culturally erasing their identity to force dependency on their rulers.
Thus, the ruling "higher" castes profounding believe in their own "superiority", and have no trouble serving more powerful foreign rulers so long as their own predation of the "untouchable" majority continues.
Hence, the very small percentage of "higher" caste Indians that study abroad identify far more closely with the WASPs than their own countrymen.
For China, after the Manchurian Qing Dynasty, generations of Chinese forged a new national identity with blood and tear that is far more equitable and inclusive. Hence, the idea of serving the motherland would be much more prevalent.
To sum up, it helps when those students don't see their own countrymen as human animals.