Treaties signed after WWI being enforced or not is NOT the point of this discussion, either.
The treaties also involved several other types of weapons that Germany was not to be allowed to have. The proper time for France & England to act was when the Germans marched into the Ruhr Valley. At that time they lacked the weapons to take it by force, had there been any force.
In any case, if the European countries cannot sustain themselves, neither can the US. Our economic system requires a growing population, and since resources are limited, eventually the US will no longer be able to do this. Perhaps Iceland has a sustainable economic system, but I am pretty sure that most of Europe, the US and most of the rest of the world does not.
And whether "American Liberals" love something is entirely beside the point and has no effect , either.