That applies during an immigration process, not after the person has a green card. But also there is a higher law, the constitution. Federal law that is in conflict with the constitution is invalid. The constitution gives "due process" and "equal protection" to everybody, not just citizens. People can certainly be legally deported, it doesn't stop that. But they can only be legally deported with "due process". And in this case, there was no due process. The Trump administration just ignored the stay issued by the court. That single act turned America from a country under the rule of law into a fascist state. You are living in fascism now.