Gosh - I had no idea about the Russian thing. You'd think they could do something more constructive with themselves.

You might think, but the Russians have been the world champions of espionage & subterfuge for at least a century. It is an enormous return on investment to deploy a few inexpensive resources and create havoc in your adversaries. Moreover, it is a win-even-if-you-lose situation; you don't need to get everyone to believe your dezinformatsiya (disinformation), you accomplish much even if people simply throw up their hands and say they don't know what to believe. The same with pushing extreme points of view in politics or hoaxes -- it pushes people to disconnect from their society, weakening that society.