When a white person in historic America encountered the negro slave trade for the first time, becoming aware of the harsh living conditions of millions of people, he have to either conclude that their values regarding justice and the human condition were either in obvious conflict with their own society and culture, or accept the narrative of white supremacy, i.e. blacks were less human and so suffering was OK because it was their natural state. Most chose the latter, as it had the least cognitive dissonance.

A Westerner observing a typical 1920's Chinese person's life for the first time would have experienced the same assault on their fundamental values, especially more humanist values. It was a feudal society, where quiet tolerance in the face of extreme hardship is a cultural value, as is producing as many (male) offspring as possible. Moreover, given harsh standard of living and the large population, human life (especially those of children) was cheap and easily discarded. Finally, post-Qing China would have seemed extremely unsanitary to Western eyes -- even today Chinese authorities struggle with promulgating basic 20th century standards of hygiene (since hygiene is a norm, not a trait).

The foreigner would have been aware that 100's of millions of people lived this way (no one knew China's population was a billion plus until the CCP did the first modern census).

It would have been all to easy to take a dim view on the Chinese as people.