The crucial point about ethnic cleansing is not about whether what drove people into exile was forcable expulsion or just fear of war, it is about whether they are permitted to return home subsequently, or whether they are refused this right, and their absence is used as an opportunity by others to take over the land from which they fled and wipe out the traces of their existence.

Most of those fleeing Syria now are not coming because they are being forcibly exiled, but because their lives were at risk in the chaos of war. If their return is prevented by a new regime in the aftermath of the war - as could well happen if a Sunni jihidist regime were to win, especially in the case of Christians and Shia - that would clearly be a case of ethnic cleansing.
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I agree with DMG. The trouble is, the last time I looked at that other thread it had turned pretty toxic. This threatens to happen here as well. Many people seem to find it impossible to remain civil while in sharp disagreement with others over matters they care about. Or perhaps they don't try, believing that civility in such circumstances is somehow inauthentic.