This nonsense is status quo for liberals. Defeat truth by limiting the debate and controlling the conversation. Illegal alien is a label that alerts the hearer or reader that the person referred to has entered the US illegally. Most often, a court decision isn’t required to ascertain that information, no more than a court decision is required to label someone as an undocumented immigrant. This is on a par with comparing those who tell the truth about Islam with the Nazis who persecuted the Jews. Extend that to those who tell the truth about the consequences of illegal immigration. Convolve truth until it is twisted into a lie.
Although I would prefer that be the case, it isn't. To actually deport someone, requires either a finding from a judge in a removal hearing (which is an administrative hearing), or a conviction at a criminal trial. Either way, the burden of proof falls to the government to demonstrate the alien is removable by “ clear, convincing, and unequivocal evidence”.
Even when we round someone up right on the border, those "illegals" have two essential rights - either voluntary removal (which almost all of them choose), or access to a removal hearing. As a matter of course, those removal hearings are pretty perfunctory.