For example, when the money was obviously not going to be repaid, but the Troika continued to lend them more -- at what point does the lender become at least partially responsible? Obviously I don't advocate irresponsible borrowing, but certainly irresponsible lending is also bad.
Ultimately, the bond holders are going to have to take a hair cut, or have their Euros devalued, because the Greek economy cannot possibly hope to repay its current debts. To think otherwise is to hope foolishly for the impossible (all questions of right or wrong aside).