Oh my,
For one you claim to have studied psychology for 35 years, you do not know much do you. You are to fixated in being politically correct. Racism and fear for foreigners is in our dna, and with right thinking of everything foreigners could bring to the table of pandemics, illnesses as well cultural differences leading to conflicts. We are trained and reached it is wrong since we are kids. Some kids are mor outgoing than others, but the norm for kids, is to be afraid of foreigners especially if family is not close by. Same goes for animals, and we are animals, do not forget that.
In prehistoric times, being cautious of unfamiliar groups could have been advantageous for survival, as they might have posed threats of violence, resource competition, or disease