The police union ordered and distributed the masks emblazoned with black-and-white American flag with a blue stripe across the middle. The symbol is associated with the Blue Lives Matter movement, a display of unity among police officers in response to the national Black Lives Matter movement.

…Police union president, Tony Montoya, said the blue line “represents law enforcement’s separation of order and chaos.” 

…”The thin blue line is a political symbol,” John Crew said. “And it’s a POA-branded mask. It’s like wearing a political button.”

San Francisco top cop bans “thin blue line” masks – CBS News

Make no mistake citizens, the police union is reinforcing the premise that our police forces’ duty is first and foremost to serve and protect their own, no matter the cost. (Spoiler: It’s not.)