What does second-class citizen mean?

It refers to those who immigrated to the United States but have no social roots there.

Americans also have human feelings, but in the American cultural system, they don’t abuse them like we do. It's just that when nothing happens, because the United States has abundant material supplies, these people's second-class citizenship status is temporarily concealed, and they feel no different from ordinary Americans. But once something happens, these people will obviously be Marginalization.

This is mainly related to social foundation and has little to do with skin color. If you have lived in the United States for several generations, intermarried with locals, and developed deeper social ties, you will be freed from the status of a second-class citizen.

Of course, if you are not a white-skinned person, it will be very difficult for you to integrate, and you will be in the difficult mode.