Nationalism was a secondary factor in WW1 (the elites failed in their alliances, and later used Nationalism as a recruiting tool, but it was not a driver), and

Nationalism was a secondary factor in WW1 (the elites failed in their alliances, and later used Nationalism as a recruiting tool, but it was not a driver), and was not related to Bosnia and Rwanda which were ethnic wars. I think you have a misunderstanding of what the term 'Nationalism' means.