What argument about nineteenth-century immigration policy does the chinese exclusion act support?

 Chinese Exclusion Act of 1882 was the first significant law restricting immigration into the United States. The Chinese Exclusion Act of 1882 was the first significant law that restricted nineteenth and early twentieth centuries setting official immigration
both skilled and unskilled laborers and Chinese employed in mining”—from entering the country... and Immigration is a hot-topic issue in the United States. This is actually nothing new

What is this saying? ?