Because the Biden administration believes its role is to protect and to serve - terrorists.

Biden admin refuses to reveal terror watchlist nationalities because doing so would violate the terrorists’ “right to “privacy”

Fox filed a Freedom of Information Act (FOIA) request in October requesting the nationalities of suspects on the FBI terror watchlist arrested at the southern border entering between ports of entry by Border Patrol.

Over six months later, CBP told Fox it will not provide the information, although it acknowledges the information is maintained in the Terrorist Screening Dataset (TSDS). 

The letter says it is applying exemptions to protect the disclosure of files that may create a "clearly unwarranted invasion of personal privacy" and must balance a public's right to disclosure against an individual's right to privacy.

Betcha didn’t know that persons on our terrorist watchlist who are arrested for entering the U.S. illegally are entitled to a right of privacy that protects them from having the public know where they came from. Well, Biden says they do, and his handlers’ refusal to breach that imaginary right has nothing — nothing, I tell you — to do with sparing their candidate from the embarrassment that would ensue if it turned out these people were coming in from friendly Arab states and Eastern European criminal dens.