To  'This article deals with contentious subject matter' is false statement. Ustashe were historic reality very well elaborated by historians of the twentieth century history. If something is highly desirable - do it, not just demand it from others. After fully being familiar with the list of given references - come then back and show the text deficiencies.
To  'Lastly, just a note about Einstein.' Firstly the text in New York Times is an opinion about something done by Einstein. Einstein is not quoted there at all. I've reviewed five books dealing with Einstein's work and life - not a single one mentioned this Einstein's support to Ustashe. Martin Broszat, the world-renown historian and university professor, nowhere in his Der kroatische Ustascha-Staat book ever mentioned Einsten in the context of the referenced New York Times article. Moreover, in the "Ante Pavelic und Ustascha-Bewegung" chapter, Broszat mentioned well-organized Ustashe propaganda in the USA. The League of Nations nor any of its bodies re-viewed alleged Einsten's 'protest' nor took any action against Kingdom of Yugoslavia. To suppress Ustashe terrorism in Yugoslavia, League of Nations sanctioned Hungary and forced Mussolini even to jail Pavelic temporarily.72.75.20.29