There were several claimed (but unconfirmed) Georgian UAV shoot downs by an L-39 and a Buk. Previously, Israel has downed two UAV with Patriot missiles, one in similar location to the recent incident.
http://www.jta.org/2014/08/31/news-opinion/israel-middle-east/idf-shoots-down-syrian-drone-with-patriot-missile

Whatever the reason for the recent failure, I disagree with the OP that this incident reflects overall performance of either SAM or AAM missiles. The reports are still vague as to what type of UAV it was, what it was doing, engagement parameters. And contrary to some people’s apparent beliefs; tactical recon UAV are not easy to track, target, and hit.

In certain respects, the interception of unmanned aerial vehicles is viewed as more challenging than bringing down fighter planes. The reason: These aircraft are smaller than fighter planes, sometimes considerably so. Their slowness makes them a difficult target for fighter plane missiles and also interception missiles that are designed to lock onto much larger and faster bodies. These qualities (or ostensible weaknesses) give UAVs certain advantages

Read more: http://www.al-monitor.com/pulse/originals/2016/07/israeli-air-force-idf-drone-russia-jets-cooperation.html#ixzz4Fjo8aavd

Add this to the comments from Tal Inbar in post #7, and the point is clear.

thx, found it:

https://www.youtube.com/watch?v=dNpABtIKERg

Any particular reason why you would have your UAV fly over treetop altitude..?

Trying to avoid having it shot down I suppose. No confirmation of altitude it was at though. Some additional info: was over Golan, there are pictures of the failed patriot launch (apparently missile exploded, no information if proximity fuse or premature). Patriots have downed drones over Israel in the past. There is no confirmation that it was a searcher 2, or Russian.

Amega, your aware of how radar works. A UAV most likely not only has a small RCS, flies low, and usually at speeds well below 160 km/h. That makes them not only difficult to track but likely to be filtered out. Or do you think that most air search radars are plotting every duck and buzzard in the vicinity?

Add to that the limitations of the seeker head to lock on to that target where relative ground speed is low with all the movement around it.

Or don’t take my word for it and read the quote I posted from the UAV expert. In other words, the failure to intercept is concerning but not particularly surprising. Trying to apply this to the success rate of SAM or AAM as a whole is the very definition of apples and oranges.

Convert all old cessnas to cruise missiles, they may take like a day to get to their targets but they will… all get there !

Worked for Mathias Rust.

https://www.flightglobal.com/news/articles/uav-incursion-strengthens-israeli-sales-ban-with-mos-427946/

As expected, nothing like what missile manufacturers would have you believe.

Do you know what a Searcher 2 UAV is? The missile is larger than the UAV! Most likely the UAV is too small, too slow, too low. Probably very hard to maintain a lock, discern target from ground clutter.
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Moderate observable? What does that even mean?

Dont ask.. Cue the graphic from NG on possble JAST configurations for the thousandth time.