A video showing a woman confronting a security guard over a patch on his uniform has ignited fierce debate online about the symbol's meaning. The footage, filmed at Northland Shopping Centre in Melbourne's north, shows the woman questioning the guard about an Australian flag patch featuring a thin blue line. 'Why do you have that on you? It's a white supremacist thing,' she says in the video. The guard initially responds, but the woman interrupts: 'I'm a historian. You need to take it off. I've seen you wear it several times.' He eventually removes the patch as she urges him...