Fannie and Freddie were private organizations with US government mandate to provide loans. The CEO's were charged for lieing about the extent of their exposure to sub prime loans.
The Financial Crisis Inquiry Commission reported in 2011 that Fannie & Freddie "contributed to the crisis, but were not a primary cause." GSE mortgage securities essentially maintained their value throughout the crisis and did not contribute to the significant financial firm losses that were central to the financial crisis. The GSEs participated in the expansion of subprime and other risky mortgages, but they followed rather than led Wall Street and other lenders into subprime lending
NIVA and NINA loans were not created by the government. ARM loans were not pushed or created by the government. Interest only loans were not pushed by the government. The government did not rate CDO's AAA.
But beyond that...back to the question of whether or not we have structural problems...companies becoming highly leveraged fueld the bubble. It was a supply side bubble which you obviously agree with since you blame the government (which in on the supply side). The funding from the bubble came from the private sector, from overleveraged financial firms.
Edit: I would like to add though I think Fannie and Freddie...private institutions that have the implicit banking of the federal government is the dumbest idea ever. I remember thinking that when learning about the structure of it in a Banking Insititutions class in college.
I also thing the implicit guarantee of bank bailouts for too big too fail institituons is the dumbest idea ever as well.