It is said that foreign citizens will become second-class citizens when they immigrate to the United States?

Not second-class citizens, but foreign immigrants. The benefits are the same, but the political rights are different. Foreigners who become American citizens only have the right to vote, but not to be elected. In addition, the United States has no welfare ~ they starve to death without money. The government won't give you money for nothing. Insurance is the same, you have to pay for it yourself.

The same is true in the United States, depending on the background of the relationship. There used to be a woman from Taiwan Province Province who later joined the United States and worked as a mayor in the United States for several years. As a result, her father is a senior official of the Kuomintang.

As for people like Yao Ming, a world celebrity, Americans envy him for having so much money, so first-class citizens and second-class citizens don't matter to others. They have the same status.