The GOP will always find a way to blame government for our economic problems. They get lots of help from conservative "think tanks" like the American Enterprise Institute, and from the Ruppert Murdoch media that includes the Wall Street Journal and Fox News.
In this case, the GOP takes the position that the financial crisis was caused by government efforts to increase home ownership among low income Americans. Fannie Mae and Freddie Mac, which are government sponsored entities, purchased sub prime mortgages from mortgage originators and caused the financial crisis according to the GOP. Fannie and Freddie did purchase sub-prime mortgages but only because its executives were concerned about the loss of market share to Wall Street banks which had entered the market and had purchased most of the sub-prime mortgages.
This is just another of the big lies that won't go away. Hitler's propaganda minister said that if you repeat a lie often enough it will be believed. Moreover, he claimed that the bigger the lie, the more believable it would be. The GOP has learned this lesson well.