Serbia is just a passing country, they stay here for a day or two and move on. If EU closes it's borders, it will be "fun", so to say.
I think violence is not that serious as one could conclude from your post. I don't know where you get the info, in our news it is not that dramatic, by a long shot. Ona new year eve, in Germany, there were sexual assaults reprorted, maybe even one rape, but ever since nothing simillar. Sexual assault can be anythong, down to holding one's hand without permission.
I'm more concerned about long term consequences, preserving autohtone culture and such. For example, our natality is decreasing, while all these people come from cultures where natality growth is one of the main faactors and so on. But if we are not smart enough, if our society is not good enough, develloped enough to preserve it self, maybe it's time for a change? Evolution takes no prisoners. Life.