Which group was most justified in its reaction to the treaty of versailles why?

It was Germany who reacted on the Treaty of Versailles. 
This was said to be the reason that pushed Germany to World War II. The Germans did not have proper representation for the treaty they were not allowed to participate in its formulation.  It made the treaty be an imposition rather than a negotiated agreement.   The Treaty of Versailles contained the complete demilitarization of Germany and the loss of their colonized countries. The Germans believed that this situation was not a fair treaty.