(CNN) -- News from the war against ISIS appears, for once, to be upbeat. On one front, Iraqi forces have launched an offensive against the extremist group's stronghold in Falluja, west of Baghdad. At the same time in Syria, the Syrian Democratic Forces (SDF) are on the move to clear the countryside north of Raqqa, ISIS' de facto capital. That is perhaps the view from afar, but as is so often the case, the closer you get to this conflict, the less clear it becomes. One might expect that the long-suffering inhabitants of Raqqa, who have been under ISIS' heavy black yoke since 2013, would welcome the approach of their liberators. But according to a tweet put out in English by the activist group Raqqa Is Being Slaughtered Silently, "the strategy of taking Raqqa by SDF... push a lot of people to join ISIS to Defense for their city." In other words, rather than preparing to welcome their would-be liberators, some Raqqa inhabitants are choosing to throw their lot behind ISIS. The problem lies in who those would-be liberators are. Backed by the United States, the Syrian Democratic Forces are a coalition of Kurdish, Assyrian, Christian, Arab tribal and other forces. But they are dominated by the Kurdish YPG, the Popular Defense Units. In other words, it's a Kurdish armed force with a multi-ethnic fa