Russians leveraged social media very well during Ferguson riots without entering. Simple scenario that always works on crowds: collect enough mass on different sides of the argument, direct them to the same location, introduce a catalyst and a detonator, and you get a critical mass right there at a laughable cost. Soros does the same. In fact, there are many players who play this game simultaneously, including the feds. If you haven't read Gustave LeBon on crowds you may want to catch up; Lenin, Hitler and Mussolini were his ardent students.
As for the EU, it has become a dictatorship long time ago. All the politicos get drunk on power, just take a look at Jacinda in NZ.
Poland is not going anywhere, it has to choose the lesser evil, and the EU is an obvious choice in their case. Otherwise, it's Mongols all over them again.
[New Unia with Ukraine, Lithuania and later Belarus would sure keep both Berlin and Moscow on their tows, but it is not feasable at the moment]