Pensions are money taken from the working classes and the capital, it doen't magicaly create GDP. Again, it feels fair that a country way poorer per capita than the US or Germany should at least match their retirement age to those country.
Corruption, red tape and over spending are the reasons why Greece is in bad shape.
Under the EU program, money taken away from the working classes goes directly to creditors. Better to give to pensioners, who did 'earn' it, based on their understanding during their working years, and at least return it to the economy.
And no one should work as much as Americans.
And finally, you can't change society overnight. Corruption red tape and over spending exist everywhere, even the US. You can't simply crack down because then capital flight occurs. There's an entire category of economics that deals with this (development economics). It's always a balancing act.
There's many reasons for the Greek crisis, its all too easy to apply moral judgement to a very complicated issue.
Edit - the concept of 'fairness' also has no place in economics. That's for politics or religion. Economists try to achieve the best outcome, not try to decide what's 'fair'.
Second, when you suddenly tell people who don't have a job (remember, unemployment is already high in Greece, especially among the youth) that they need to find one, it leads to a further strain on employment, and societal tension.
And remember, pensioners spend money. The money may come from the government, but it goes into the economy. If this money isn't going back into the Greek economy, the GDP decreases.
These measures will only increase unemployment and decrease GDP further. Exactly the opposite of what Greece needs. It may seem like a small thing, but on a macro scale, small changes add up.