The Jersey City shootings were committed by Black Hebrew Israelites, a typical black cult which hates whites, but concentrates on hating Jews because the Black Hebrew Israelites think that they're the real Israelites.
Palestinian-American congresswoman Rashida Tlaib, hearing that there had been an anti-Semitic mass murder, tweeted and deleted this: "White supremacy kills."

I think she thought that if they weren't white, the media would have said so.
The View's Joy Behar made the same mistake:
Can't load tweet https://twitter.com/theblaze/status/1205159167855644674?s=12: Unknown MIME type: text/html
Did Ms. Behar think that if they weren't white, the media would have said so?
The New York Times's Ali A. Watkins did an article about the NYPD investigating anti-semitism that didn't say so.
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When black gunman DeWayne Craddock committed a "Disgruntled Minority Massacre" in Virginia Beach, this appeared on Twitter:

[Tweet (deleted after two days of protests) | Archive]
The lady who posted that may have hated white males already, but here she was the victim of MSM suppression. She assumed that if the "longtime city employee" wasn't white, they would have said so.
They won't if they can possibly help it. But if the gunman is white? Boy, will they mention it!