If I were to lend 10.000 euros to someone, I'd have a better chance of having that loan paid in full from a German citizen living and working in Germany than from a Greek citizen living and working in Greece. That does not mean that I would not lend to Greece, but it means that I would take a higher interest rate to compensate for the risk.
Which, on the other hand, means, that it should be possible that this risk of Greece not paying back should also be realized. However, Greece was "bailed-out" which means the investors were bailed out instead of sucking it up that they did an insecure investment. In 2010 about 100% of the investors in Greece debt were private investors (Deutsche Bank for instance), now it is the tax payer who will lose if Greece declares bankruptcy.
It is not a diabolic German plan to put Greece down. It's just economics.
Actually, there is a plan to put the current Greek government down, because if they somehow succeed to get Greece back on track than this is a signal for Spain, Portugal, and maybe even more countries in the Eurozone that a different politic is possible than is not based on the austerity dictated by Germany.
Incidentally, there are general elections in Spain in November, and yesterdays communal elections showed that the anti-austerity movement goes strong. If they could point to Greece as an example of how to do it differently, then it's bye-bye for the currently ruling party.