A reminder about your rights. If the government can declare you to have an attribute that negates your rights, then you have no rights.
In laymen's terms, if ICE arrests you and fast deports you, whose going to stop them? Okay but you get to a consulate in the foreign country and get back home. When you come out of your lawyer's office (because you're suing ICE), ICE arrests you again, this time as a criminal illegal alien because you came back in. They tell no one they have you, they tell no one where you are. You have no rights according to them. You are sent to an El Salvadoran prison in contravention of a court order not to deport you.
These are all things that have happened separately. We've accidently deported Americans. We've deported Americans on purpose. (Trump sent American kids away so he could deport their parents too) We've deported someone to an El Salvadoran prison in contravention of a court order.
If they don't have rights, then neither do you because the government can just declare you a member of that group and as long as the guys with guns maintain that fiction, nobody can stop them.
This is also blatant misinformation. No judge ever made a finding that he was associated with MS-13. The government asserted it in court but it's never been proven. The immigration proceedings largely revolved around his asylum application, interview, and testimony.
So they're lying in an attempt to make it sensational enough to bust past due process. For an example of how that looks long term, check Duterte's regime in the Philippines. Many people were killed extrajudicially and written off as drug dealers.