David Bier, a Democrat-called witness at a Senate Budget Committee hearing Tuesday, drew a sharp rebuke from GOP Sen. John Kennedy of Louisiana after accusing the Trump administration of attempting a "population purge" in the U.S. Earlier in the hearing, Bier, an immigration policy expert at the CATO Institute, argued that both legal and illegal aliens "are a benefit to this country" because they help to reduce the national deficit. Kennedy ripped into Bier, asking, "What planet did you parachute in from? You trigger my gag reflex." Bier had just claimed that federal judges opposing President Donald Trump’s immigration enforcement operations "are much braver" than U.S. Immigration and Customs Enforcement officers. **FAMILY DEMANDS FAR-LEFT PROSECUTOR BE OUSTED FROM OFFICE AFTER SISTER KILLED BY REPEAT VIOLENT OFFENDER** "They are much braver. They put their names on their rulings, and they stand behind their constitutional rulings," said Bier.…