Like Jayson Blair, he was just making stuff up. [The Intercept Issues Mass Correction After Writer Caught Fabricating Quotes by Alex Griswold, MediaIte, February 2nd, 2016]
The New York Times, as noted by Eugene Gant, covered this as St. Louis Man Charged With Making Bomb Threats Against Jewish Sites by Benjamin Weiser, March 3, 2017 . Earlier coverage of the same threats by the same paper came out like this:
Trump, and his mostly white, Christian supporters are not anti-Semites.
Here are two quotes on that.
The Jewish Telegraph Agency:
Trump is from New York, works in professions saturated with Jews and long has been a vocal supporter of Israel. His daughter and two grandchildren are Jewish, the executive vice president of his organization is Jewish — and Trump certainly has chutzpah.[When it comes to Jewish ties, no GOP candidate trumps Trump, by Uriel Heilman, Jewish Telegraph Agency, August 8, 2015]Lion of the Blogosphere:
If Trump becomes president he will be the most culturally Jewish president in American history. His daughter is Jewish, and probably a plurality of his top employees are Jewish. ...That's Trump. Barack Hussein Obama, on the other hand, supported and was supported by black Muslims, including Louis Farrakhan and Al Sharpton. This is a typical Obama supporter crime. See if anyone calls it that.
Also, Trump once served as the grand marshal of the Salute to Israel Parade.
Irony Of Trump And White Nationalists, December 14, 2015
But what ties Jayson Blair, the black reporter who was fired from the NYT in 2003 for lies and plagiarism, Juan Thompson, fired from a news site for almost exactly the same thing, and Barack Obama, whose presidency will be remembered for spawning riots and murders across America, are two things.