As an individual, I agree that if you voluntarily borrow money, you are in a binding contract and the debt should be repaid. This is of course is not an absolute, as we have bankruptcy and default. But as a matter of good business practice, yes, debts must be repaid.
So what do you do in a case where the actual debt and repayment terms are created by the lender in concert with corrupt government leaders. The lender pays to get favorable terms and corrupt government officials use the money to enrich their supporters and maintain their political power. Neither has any concerns about the effect this debt will have on their population and their descendants, whom will be paying interest on this debt their entire lives.
The rules of the game are fixed by a small elite at the top of the political /economic ladder. They do this purely to benefit themselves and maintain control of the masses. The fact that this debt load cripples the economy and reduces the standard of living of everyone is of no consequence to them. All that matters is that the interest payments are made in full and on time.
So now that I'm finished talking about the United States, let's talk about Greece. Yes they are socialist idiots (oxymoran), but they still deserve a chance to be free and to prosper. Will they choose this path, I seriously doubt it. All the smart ones have left the country long ago and the slaves that remain will fear change and increased responsibility and accountability.
What Greece should do is to ditch EU and default on all their debt. Basically stick one in the eye of the Global Governance folks. By pushing the reset button, they get a fresh start and if they can commit to behaving like adults, they can make Greece a better place.
Establishing a New Dracma based on Gold or Silver would be a good start. The U.S. Treasury was required to have 40% physical Gold reserves when we were on the Gold Standard and this would be a good standard to aspire to.
Having Zero business, personal income and wealth taxes would draw companies to Greece in the long term and simulate the local economy in the short term. Real Banking Privacy (Secrecy) like the Swiss used to have would also bring in cash liquidity in the long term.
Sale of Government owned property/land and reliance on (low) import duties would provide some revenue. Sin taxes, (small) sales tax, fuel taxes, etc. would also be sources of revenue.
Pensions would have to be cut and funded from payroll taxes. People under 65 years of age would need to work and some will have to be "un-retired". The civil servant class would be mostly fired as the majority of government workers in Greece are a drain on the economy.
These are just the beginning of what would be required and the Greeks simply have no stomach for it. As long as the power stays on and they have some food, the slaves will be content.
The great majority of the U.S., the 55% of the population whom rely on Government handouts to survive will likely feel and act as the majority of Greeks now do.
Our Founders gave us a Republic, whether or not we can keep it, is in doubt.