Masked neo-Nazis had a surprise march through DC, MPD says masks were legal [View all]
After video of the event spread, civil rights activists and legal observers asked how the demonstrators were not in violation of the Districts anti-mask law.
https://www.wusa9.com/article/features/producers-picks/masked-neo-nazi-protest-dc-was-it-legal/65-4872c9c8-2ab7-423b-b45f-1e9fe9b8c017
WASHINGTON In an unannounced demonstration through U.S. Capitol grounds and the National Mall, masked neo-Nazis issued a clarion call to their cause, as stunned tourists and neighbors looked on.
Members of the white nationalist group known as "Patriot Front" shouted chants of "reclaim America," as they crossed Constitution Avenue. Their yells echoed against the stately buildings of the government they seek to remove.
"These people are neo-Nazis from Charlottesville who killed Heather Heyer," a counter-protester said, referring to the 32-year-old activist murdered during the August 2017 Unite the Right march. "Do not let them into D.C."
Patriot Front is defined by the Southern Poverty Law Center (SPLC) as an image-obsessed hate group, founded in the aftermath of Charlottesville.
Around 150 members of the organization were difficult to miss on an otherwise tranquil afternoon young and middle-aged men wearing matching khaki pants, white face masks, black sunglasses and khaki hats.
But after video of the event spread on Twitter, civil rights activists and legal observers asked how the demonstrators were not in violation of the Districts anti-mask law.

Video at link.
There's always a loophole