Germany did start the war by itself. Not the smaller Austro-Serbian war, but I think that must be viewed as seperate. That does not mean Germany should been denied a negotiated surrender, nor a place at the peace table. It wasn’t always that the one who started it was forever the Bad Guy and deserved whatever they got from the Good Guys. The treaty could’ve been fair even while acknowledging who started it, which is seperate from “guilt.” Especially when the other side did things as bad or worse after the war was underway.
I don’t acknowledge the “hence” in your post. Blaming Germany and burdening it with costs made Hitler more likely but not inevitable.