"The housing crisis was caused by the banks and their deregulated policies revolving around the subprime mortgage issue." (Michael Lambert)
This is more specific than most of the fallacies here, so perhaps it should be moved to another list at some point, such as Statist Errors. Also note: "financial crisis" and "housing crisis" are being used interchangeably here to refer to the same event: a financial meltdown tied directly to housing markets.
Tom Woods has written extensively on these issues, so let's just go directly to a few of his relevant articles:
The crisis was contributed to by government policy to increase homeownership via such acts as the "Community Reinvestment Act" (although it was by no means [article overstates but has some facts] the primary nor sole cause).