These fact checks are against a different claim, namely "detainees are free to walk out of detention centers" or "voluntary deportation is granted to everyone w

These fact checks are against a different claim, namely "detainees are free to walk out of detention centers" or "voluntary deportation is granted to everyone who requested it". The claim that nobody has made. They are being detained because they claimed asylum (likely just to evade being deported) after illegally entering the country. They are being held while their claim is being evaluated. If they were to abandon that asylum claim there would not be any reason to hold them and the deportation would proceed. Voluntary deportation may not always be available since it's a privilege at discretion of immigration officers but forceful deportation is always there. The difference is that you get a ban on entering the US after being deported and voluntary deportation leaves your record clean. E.g. the most recent case of a 18 y.o. held in detention: https://www.dallasnews.com/news/immigration/2019/07/22/dallas-born-citizen-picked-border-patrol-detained-three-weeks https://www.dallasnews.com/news/immigration/2019/07/22/dalla... Whose brother, who had no citizenship claims had apparently been deported as soon as he signed paperwork: "After two days in detention, Marlon signed a voluntary deportation form." If you need more information there are plenty immigration lawyers websites explaining the whole procedure and options for detainees.