The problem is that in this case the "debt fuly owed" is one's life. If you look at the history of the world you will find that prior to social welfare programs, the ultra wealthy were not taxed, they were killed. Time and time again through history, when a single person amassed too much power or wealth, the poor and needy would rise up to take what was built upon their broken backs, and in so doing taking the life of those that would oppress.
This is why I promote the abolishment of taxation. Not because of some objectivist pipe dream, but because when given no other choice, the people will rise up against their oppressors. Go ahead 1%ers, and probably even 5%, who I happen to be one of, stop giving to those in need, and see what happens next.