Waking up?

From every corner in Washington DC, reasonable voices can be heard arguing for the necessity of regime change in Iran. Robert Kagan favors the change, Richard Haas has voiced his support for Iran's Green movement and Robert D. Kaplan has urged Obama to be more like Reagan in dealing with tyrannical regimes. Now another ex-government official has come out in support of regime change in Iran:

For some Americans, the idea of regime change is tainted by the Iraqi invasion and occupation. But there is also the model of South African regime change, overturning apartheid with massive international pressure, and Polish regime change, aided by covert American support for unions and democratic resistance.

However my question is why didn't these same people promote regime change when they worked for the government? Why now? Whatever the answer may be, it is not too late. Sanity and reason is always appreciated.