The actual answer, I think, is that Hollywood tends to cast Eastern European characters in villainous roles. Daniel Bruhl and Christoph Waltz are mostly cast as villains as well. Even when they're not, they tend to play off those tropes (like Bruhl in Rush isn't villainous but is seen that way by others, or Waltz in Django as a direct subversion of the evil German trope).

If you watch Mikkelsen's Danish films, he gets much more complex roles.