Why did the leaders of great britain and france demand that germany make large reparations

During the Treaty of Versailles they decided all blame should be put on Germany, and a punishment was to pay for all of WWI's damage. This was also to keep them so low in money they couldn't possibly come back to the top and go back to war again. (They literally only fully paid the debt of 33 billion in about 2011)

To pay back for starting world war 1