Link: https://www.the-independent.com/news/world/americas/us-politics/bryan-morales-us-citizen-deport-mexico-b2955205.html

A man deported to Mexico has claimed that officers not only refused to see his documents but accused him of fraud

A U.S. citizen has been deported to Mexico despite telling arresting officers that he had proof of citizenship at home, according to a new report.

According to Univision’s Lidia Terrazas, 25-year-old Denver-born Brian Morales was threatened with either deportation or prison time following a traffic stop in Texas by Customs and Border Patrol (CBP) agents.

This is the latest in a string of incidents involving U.S. citizens and Department of Homeland Security agents during the first 18 months of Trump’s second term in office. In addition several American children have been deported alongside their parents, including a child undergoing cancer treatment in the U.S.

The worst of the worst, are agents of ice

For the last time, he was exiled to Mexico. You can’t be “deported” from a country you’re a citizen of.

Yes you can... It's just illegal to do so in most countries.

That is actually an easy fix, they can just strip you of your citizenship. It happened many times during the second red scare.

According to Morales, his boss was also placed into ICE custody, despite being a U.S. citizen with proof of citizenship at home.

Since his boss was detained as well, there should be enough sympathy/empathy that Morales won't lose his job over lost time from being deported.

I know I'm being pedantic, but it's not a question of legality; it's about the definition of the word.

That being said, the most frustrating part of semantics, of course, is that definitions change over time.

They don't need a conviction of some kind?

Illegal deportations are still deportations. The composite parts of the word just mean "to carry away", there's no requirement for the act to be legal. A pretty famous example of illegal deportations is nazi Germany deporting Jewish citizens.

*deport(v.2)

"banish, transport or carry off from one country to another, especially forcibly," 1640s, from French déporter, from Latin deportare "carry off, transport, banish, exile," from de "off, away" (see de-) + portare "to carry," from PIE *prto-, suffixed form of root per- (2) "to lead, pass over." Associated by folk etymology with portus "harbor." Related: Deported; deporting.
https://www.etymonline.com/word/deport

"Anyone who attacks our values ... we're going to come after aggressively."

A secret tribunal was enough during the red scares. Sometimes the evidence used was a book that included subversive behaviour which the FBI obtained by breaking into a house. Sometimes it was an informant who may or may not have been telling the truth.

I suggest you read up on the red scare.
Red Scare: Memories of the American Inquisition: Memories of the American Inquisition: An Oral History