The real question is why they thought that was a smart move....
They're like Alfie Allan's character in John Wick: they're so accustomed to being "made men" living under another's protection that they think they're invulnerable. They think that the man they're chasing down will fold, like the couple who didn't shoot and kill the lynch mob that tore down their front gate, but were still prosecuted just for presenting a facade of resistance. After months of looting, burning and general mayhem they think they've won, and that nobody would dare defend themselves.
They're like Alfie Allan's character in John Wick: they're so accustomed to being "made men" living under another's protection that they think they're invulnerable. They think that the man they're chasing down will fold, like the couple who didn't shoot and kill the lynch mob that tore down their front gate, but were still prosecuted just for presenting a facade of resistance. After months of looting, burning and general mayhem they think they've won, and that nobody would dare defend themselves.