i don't know why you keep calling him uncle Joe but its really lame lol. In regards to your question of was it the only 'start', well yes it was since that is when you know, the war started. Poland had allied itself with both France and UK and did it recently so obviously France and Poland drew a line for Germany. Anyways, by the time of Poland, the treaty of Versailles had been largely reversed and the reason why the war started was not just Versailles but the larger ideological Nazi framework and needing a war to achieve their aim of "Autarky" or self sufficiency from the rest of the world economy which they believed was controlled by Jews. They had the insane plan to not just conquer the East, but to then subject its people to annihilation and enslavement.
Here is a quote from Hitler:
“The [eastern] region must lose the character of the Asiatic steppe, it must be Europeanized! It is for this purpose that we are building great highways to the southern tip of the Crime and to the Caucasus. German cities established along these roadways will stretch like a string of pearls, and around these will be German settlements. The two or three million people we need [for this program] can be found quicker than we think. We will take them from Germany, the Scandinavian lands, Western Europe, and America. Chances are that I will not live to see this, but in twenty years twenty million people will inhabit this territory. In three hundred years we will have a blossoming parkland of extraordinary beauty!
There is only one task: Germanization through the introduction of Germans [to the area] and to treat the original inhabitants like Indians. … I intend to stay this course with ice-cold determination. I feel myself to be the executor of the will of History. What people think of me at present is all of no consequence. Never have I heard a German who has bread to eat express concern that the ground where the grain was grown had to be conquered by the sword. We eat Canadian wheat and never think of the Indians."
http://www.worldfuturefund.org/wffmaster/Reading/GPO/gpo sources.htm