All immigrants? I work at a nursing home and today the administrator had several doctors in for lunch. Two appeared to be Indian and one maybe Chinese, and one I’m not sure, but none were “American”. The future of medicine in America. I doubt they have low IQs.
This excerpt from the posted article should answer your question:
“’The average IQ of immigrants in the United States is substantially lower than that of the white native population, ... .’ He argued that ... allowing in immigrants with high IQs would help solve the problems.”