The occupiers postured themselves as armed resistors. Like a bank robber saying to a teller "I have a gun", it's prudent to believe it. I don't think there is any reason for LEOs to have thought the occupiers weren't armed and weren't willing to shoot. Finnicum got himself shot, IMO. He could have surrendered at the first stop, could have kept his hands in the air, could have obeyed commands, but no. He got what he was after.