There's SO much wrong with what you're saying. I hate that these things happen too, but ... stop the absurd hyperbole. This isn't criminal prosecution in any way shape or form.
1) ZERO citizenships are being "decreed invalid". I don't know where you get any ideas to the opposite.
2) revoking a visa does not involve a trial. ANY border control officer can do that, for any reason, including for no reason. This has always happened, including under Biden or Obama, only the reasons have changed (a bit)
3) only removing a green card requires "a trial". It's specified between scare quotes because it is called a trial but is NOT subject to the normal rules of justice (to give one extreme example: you do not have the right to a jury trial, you don't even have the right to be present at trial). The judges are employees of the executive (hired and fired, NOT appointed) and thus under the control of the executive (ie. Trump).
It's definitely a step up from the visa "process" but ...
It's like "youth court". It's called a trial. It happens in a courtroom. In youth court, the judges are actual judges. BUT IT'S NOT A TRIAL. You don't have the right to defense. You don't have the right to a jury trial (or the same as immigration, you don't even have the right to be present).
4) You can leave ICE detention by "self-removing". This involves proving you've booked a flight, and they will bring you to the airport to catch your flight. So you're not detained.
5) this is just utterly ridiculous: "One of the many reasons we have trials is to ensure that the agency actually caught the right person"
Yes. But these are NOT trials (even the green card removal isn't). To get US citizenship you must prove yourself for, at minimum, 10 years, often more, the the executive of the US government.
6) I would ALSO like to point out that what Trump is doing is the norm in the whole world. Including in Europe. In the Netherlands, protesting while on a VISA is stupid, and if you get arrested, you will be removed. Maybe not the first time, but it will happen. I hear France is the same.