Why would they? Obama wasnt in power during the crash. What he did was make things worse *after* the crash.
There is an odd factor or two. There were several folks around who were predicting this already in 2006 timeframe, and getting no traction because no one from the Fed wanted to hear about the issue.
I might also go back to 1929, and discuss the whole decade prior to that crash...how dozens of warning indicators existed and no one (not the banks, the Fed, Congress, or the President) wanted to step into the middle of the mess.