What has changed?

I have been reading The Great Gamble: The Soviet War in Afghanistan by Gregory Feifer. Among other things, the book describes the provision of weapons to Afghanis by Russians, Americans, Pakistanis, Iranians, Saudis and Chinese during what was clearly a civil war. No one seems to have asked the United Nations if doing so was permissible.

I am watching the news as I write this, and apparently no one is willing to supply the people of Syria fighting against the Assad Government with weapons without some kind of multilateral authorization. The Russians don't seem to see any problem in supplying arms to the Assad Government.

What has changed? Was support for the anti=government participants in Afghanistan in the 1980s only due to the Cold War? It would seem that the people fighting against the Assad Government's troops are at least as worthy as the Taliban insurgents in Afghanistan in the 1980s.