It seems that they were conditionally approved, thus it says, "they were bound for a new life in America after what should have been a brief sojourn in Austria for visa processing," but that they must first leave their country in order to be further screened:
Applicants are vetted before they apply for an Austrian transit visa. Once in Vienna, they continue the screening process, pass interviews with Homeland Security and undergo medical exams. Typically, it takes a few months to complete the process, and the approval rate is close to 100 percent.
Something seems amiss, but note that "evangelical Christians, who make up more than 90 percent of the Lautenberg pool and hail mainly from Ukraine, continue to arrive as usual, but these "Iranian Christians" seem to be a aberrant sect, Suhaib Nashi, president of the Mandaean Society of America, said he feared for several Mandean families in the Vienna group. Like the Baha’i, Mandeans, who follow the teachings of John the Baptist, lack even the nominal protections of the Iranian Constitution and are thus particularly vulnerable to persecution and pressure to convert to Islam.
The Mandaean religion is a Gnostic religion (the only surviving one). They revere John the Baptist along with a number of Biblical figures (but not Jesus), but it doesn’t look like they are actually descended from the real-life disciples of John the Baptist (who wasn’t a gnostic).