Some of the Marshall Plan monies were grants, some loans. Germany had repaid the loan parts by 1971. But I guess that does not fit the author's narrative.
Has Germany ever reimbursed the U.S. for its military presence? Has Germany ever reimbursed the U.S. for its on-way tariffs on U.S. goods? Does Germany pay its fair share for NATO? The UN?
Those loans amounted to a pittance, walking around money. But if you need something to bitch about, fine.