Chinese immigrants to the United States often had an even harder time finding acceptance in their be county than immigrants from Eastern and South Europe. What was on reason for this?

Most likely because of 2 reasons.
1. Chinese immigrants were not white. The 1960s were an especially hard time for immigrants in America due to segregation so of course people from China with a yellow skin color, different style of clothing, and different lifestyles will be seen as outcast and not normal to white Americans.

2. Chinese immigrants spoke another language. Of course the 1960s there was no such thing as Rosetta Stone or Duolingo so Chinese immigrants speaking primarily Mandarin and other dialects had a difficult time learning the dominant language in America which is English. Chinese immigrants had to learn from their surroundings and during that time, but during that learning phase, finding food, asking for directions, and finding addresses was difficult without speaking, reading, or writing English.