Some Protests Against Police Brutality Take a More Confrontational Approach

PORTLAND, Ore. — Terrance Moses was watching protesters against police brutality march down his quiet residential street one recent evening when some in the group of a few hundred suddenly stopped and started yelling.

Mr. Moses was initially not sure what the protesters were upset about, but as he got closer, he saw it: His neighbors had an American flag on display.

“It went from a peaceful march, calling out the names, to all of a sudden, bang, ‘How dare you fly the American flag?’” said Mr. Moses, who is...