The rise of the Sverigedemokraterna was a predictable phenomena.  People are threatened by The Other and when immigrates comprise 12% of the population, arriving in so short a time, it strains the social fabric.  Both from the existing population and from the arriving population; refugees create especially high tensions since they, most likely, didn't want to move in the first place, don't want to be were they are, and lack the psychological basis for acculturating to their new countries mores, daily life, & so on.  

This is a big reason the US has had a strong, continuing, history of nativist 'Know-Nothing' streak; one we're seeing played-out with Hispanic immigration today.  

She believed in nothing; only her skepticism kept her from being an atheist. -- Jean-Paul Sartre