Thursday afternoon’s appearance showed the mayor is losing goodwill among the very people who overwhelmingly elected him, on the very issue that elevated him in a crowded field of candidates in 2013.

“I got two black sons and I’m afraid when they go out. I call them every day to make sure they’re safe,” Donna Clinkscales, a 60-year-old longtime New Yorker, said during a Black Lives Matter march over the Brooklyn Bridge, following the Cadman Plaza gathering.

She said she voted for de Blasio, as did most black New Yorkers who cast ballots in the 2013 and 2017 elections, making her part of his most reliable base of support. But on Thursday Clinkscales said she has lost faith.

“He hasn’t done anything for police reform. He keeps supporting the policemen, and they’ve shown, time and time again, that they don’t care,” she said.