I'm glad that you asked :)
I think that yes, a lack of economic growth (in some cases) and an increasing disparity in wealth (in others) makes people angry, and distrustful, on the long term. I also think that "oligarchies stole the money" is an incredibly simplistic explanation for the lack of growth- there are at least two factors, the competition from emerging countries and software, that have removed low skilled and low added value jobs from the West. But still the countries who kept up with their industry and education managed to thrive.
On the other hand, the people's anger doesn't come with an understanding of the issues and their causes; it's more of a general bad mood that disrupts everything, what is wrong and what is right in the same way. So that people fight against the problems and the solutions alike.
And yes, I think social media act as a multiplier of this unproductive anger, because they give a voice and an audience to those who lack the minimal educational standards that have been traditionally required to those who wrote for the public. It's classist? Fair. But it's true.
Information used to flow from an educated elite (think of the incredibly ponderous and boring articles of Marxist newspapers, if you want) to the masses, who tried to absorb and follow (with all the risks that this entailed, as well). In Italy the single voice of the communist party, through its press, could reach every peasant and set the line. While now the communication is horizontal and universal, and angry, uninformed opinions spread and reinforce each other. It's clear since a long time (think of tabloid covers) that indignation, outrage, scandal are extremely successful memes. They survive and spread replacing everything else. We need to learn how to deal with this, not with censorship, but culturally.