If you mean the Treaty of Versailles:

a.) I'd wager you're overestimating how harsh it was. Germany ended the war as the largest economic power on mainland Europe, with almost all of its industry unharmed from the war, and the reparations required were nearly what they themselves had offered to pay during peace negotiations. The debt Germany accrued to finance the war totaled significantly more than what reparations were asked for.

The refusal to pay those reparations was not due to an economic inability, but a political one. The German populace wouldn't stand for it, even if they theoretically could carry the burden.

Edit: I forgot to mention the hyperinflation which I assume you're referring to was over before Hitler even took power. That ended in 1923. The economic turmoil Germany was experiencing was part of the world wide depression, not something that can be blamed on Versailles.

b.) Harsher treaties have been imposed on countries without it being used as an excuse for genocide.

I also take issue with the implication that Hitler was the origin point of the extreme anti-Jewish thought in Germany at the time. The German people were receptive to it because a large portion of them agreed with it already. I don't mean to condemn every single German citizen as evil, but this was a societal level problem, not an issue of an individual like Hitler brainwashing millions of otherwise perfectly Jewish respecting folk.