I can't say that it's a matter of 'democracy' but simply human nature on the large scale. Personal and mass behavior (personal in the aggregate I guess) is going to be steered by a combination of top-down force and bottom-up culture. Diversity implies a lack of bottom-up control systems so, if anything, you need less democracy in modern states.
Obviously social media makes it easier to gin up a mob, and there's always been the truth that small yet loud contingents can punch above their weight, but it seems to me that there's nothing really new here. Social media appears to allow impolite behavior at lower cost, but that poor behavior was always built into the individual.
Perhaps what I'd like to hear is some insight from a participant in the Yugoslavia breakup.