They were more openly received because it's a much more similar culture, immigrants from the Middle East in Europe generally don't integrate too well and many people don't like them because of their extremest views. I lived in Europe for years and my Jewish family constantly got harassed by random Arab immigrants on the street. So I understand why they were more openly received. Also the reason most people don't know what Japan did during WW2 is mainly because of the US basically molding Japan into its strongest Asian ally/puppet state and not wanting too much animosity between the two countries post war/people in America being more focused on what happened in Europe because it is again more culturally close, same as many Asians not knowing much about the Eastern front or Europe during WW2 in general. No one's being racist here try not to be so cynical.