Gotta agree with Habte with this one, for slightly different reasons.
Of course, they ought to arm to protect themselves - lest they become impotent, especially since they're caught between warring sides and their sponsors (the Gulf countries for the opposition, Iran for Assad). But one other recent case where this happened, the Lebanese civil war, led to vicious intra- and inter-sect fighting, and in the end I find it hard to argue that Christianity as a Gospel (as opposed to a sect) did anything but lose from the process. And even from a sectarian perspective, the Christians, perhaps inevitably given demographics, lost.
The story of the South Lebanese Army is instructive - the former were pushed into the arms of the Israelis by Palestinian guerrillas, organized and began to fight a really dirty war, as such wars are in the Middle East. The SLA disintegrated in the face of Hizbullah - in what I assume was an equally dirty war on both sides - and all its members were deemed collaborators.
"Politics" in the Middle East often is a dog-eat-dog fight where you put yourself on top, your sect below you, marginalize other sects, kill those who resist you, and play outside powers for your advantage. Assuming that this report of Christian militias joining the government side is true, this not only makes them stooges of the government, but also invites at least partial massacres once the rebels take power (which I think IMO is inevitable - Assad and the Alawis are doomed - i.e. doomed to be ethnically cleansed - if not now then in the next decade or two).