Dubya had eight years to address all of the policies that he inherited from Carter and Clinton. Somehow we are expected to believe that Dubya as well as Reagan and GHW Bush were powerless to reverse Carter’s policies if they were still a problem when Dubya was president.
You state that the American Dream Downpayment Initiative money came from private sources when in fact the Heritage Foundation pointed out that the bill authorized $200 million per year in taxpayer money to fund the giveaway.
http://www.heritage.org/research/reports/2003/12/american-dream-downpayment-act-fiscally-irresponsible-and-redundant-to-existing-homeownership-programs
And this wasn’t the only enthusiasm Dubya had for the housing bubble. He routinely boasted of the size and strength of the housing market while the bubble grew, and never once objected to the exotic subprime loans that permitted the increased home ownership that was a goal of his administration. The sole problem he ever voiced was the insufficient capitalization ratio of Fannie Mae and that had nothing to do with the danger of exotic subprime loans being given to marginal borrowers.
Trying to excuse Bush for his role in the housing bubble simply won’t wash. You only need to read his speech to HUD to see where he stood and it was an enthusiastic endorsement of their policies:
https://georgewbush-whitehouse.archives.gov/news/releases/2003/12/20031216-9.html
Praising homeownership as a worthy societal goal and the legitimate progress toward that goal is hardly the same as coercing banks into giving out mortgages to people who likely can't pay them back, pushing the Fannies to cover those bad loans at government expense, and encouraging the resale of repackaged loans into the public market, especially when it was known at the time that those practices were possibly going to damage the wider economy
Fannie Mae Eases Credit to Aid Mortgage Lending. Bush was not pushing mortgages for those who couldn't afford them. He was trying to cover those toxic loans already in the system, and the undercapitalization of Fannie and Freddie was a major problem area. Their overleveraged position meant that should the mortgages they held decline little more than two percent, they would be technically wiped out. From the first year the Bush administration tried to introduce new regulations on the FM's, including requirements for increased amounts of cash on hand, preapprovals of new loans, and limitations in portfolio size. From the beginning the Democrats fought their efforts. The GSE's were fiefdoms and cash cows for the 'rats, and their henchmen were making big dollars for themselves and the party in their salaries, fees and bonuses (many obtained through shady bookkeeping as it turned out). As Maxine Waters observed at one point "We do not have a crisis at Freddie Mac, and particularly Fannie Mae, under the outstanding leadership of Mr. Frank Raines". Finally in 2005 the administration got a reform bill out of the Senate Banking Committee, but Senate Democrats were unanimous in saying they would filibuster it, and it never got to the floor for a vote. Eventually Fannie and Freddie held over half the mortgages in the country, and 45% of those they purchased between 2005, when the bill failed, and 2007 were subprime and other nonprime loans. Finally as the housing market collapsed in 2008 taking the FM's with it, the Democrats voted for the Bush regulatory measures which might have made the collapse not nearly as severe had they been more cooperative sooner. There's simply no equivalency between the Democrats' and Bush's contributions to this disaster.....