Why is the government trying to fix a problem by doing what they did to start the problem?

It is apparent that the government created the housing market burst through government backed organizations such as Fannie Mae and Freddie Mac. Other factors such as the devaluing of our dollar (thanks to Bush's monetary policy) contributed to the economic meltdown we are all part of at the moment. So, my question is: why is the government trying to step in to create the same kinds of policies that got us into this mess to begin with? Home buying and car buying tax credits sound awfully like what Fannie and Freddy did. Attempting to force people to buy products through tax credits is doomed to fail I have no question.