Watch out because “Russian law”, like “Soviet law” is anything it wants it to be at any time, and you, my friend can be labeled “an enemy of the state” at any time.
Russia has no Rules of Engagement. We saw that in Chechyna and Afghanistan.
What they are doing is to category, according to “Russian law”, any dissidents fighting against Assad, including the good guys (if there are any left).
Give a KGB guy a finger and he’ll take your whole arm off.
What he says is value-neutral in that what he means is, any strategic enemy of the client (Assad) is therefore to be defined as a terrorist. This may be good in some ways but bad in others, depends on how it is applied in future situations as more actors enter the stage.
At some point, for example, the IDF or NATO could be defined as terrorists. Or one step removed, forces directly supported by them could be so defined.
On the positive side, any realist by now must have realized that stability in Syria can probably only be provided by Assad so that the sooner all of his active enemies are neutralized, the better.
How this avoids escalating into something really dramatic is now pretty much in God’s hands because otherwise there is no adult supervision.
Unless someone promised them lots of good stuff to fight a war by proxy.