This, plus Syria is far more efficiently locked down than any of those other countries. Foreign press have a FAR harder time getting in, if any get in at all, and the father-to-son Assad/Syrian Baath party dynasty exercises far greater control, backed with Saddam Hussein level violent oppression, of its populace.
Therefore, the populace itself has less and far more restricted and censored access to it's own internet-level levers of expression. The Syrian government's control of both the foreign press and its own people means we don't get news from there.
For instance, not many here seem to know that in the early 80's, papa Assad's troops crushed a rebellion centered around the town of Hama, killing between 10,000 and 25,000 people in the process.
Other uprisings have been brutally put down over the years.
The Assad led Baath party in Syria is nasty man, they mean business.