Why should they give the money back? They used it to help the poor. Social Justice does not mean the same thing to the Catholic Church that it does for your political beliefs of what it means. Social Justice is upholding the teachings of Christ to love one another and to help those who need help. Not your definition which is what the left has perverted it to mean...like many other things...like marriage.
I think you have been suckered by an anti-Catholic propaganda piece.
I know many Catholics, many very pious, honest people whom I have the deepest respect for, and who would immediately tell you 'why'. Therefore, maybe it's a subject better left for discussion among your fellow Catholics.
No one can serve two masters. Either he will hate the one and love the other, or he will be devoted to the one and despise the other. You cannot serve both God and Money.