So did the housing bubble occur because of de-regulation...?

Both. The CRO legislation and the FED lowering rates to 1% was the cause of the housing bubble. Banks and Fannie and Freddie wasnt actively regulated properly along with consumer debt. Democrats enacted the CRO and was the overseers of the mortgage companies. Bush did not have power over either but did warn them on several occasions but as we all know the president gets the credit or the blame if its deserved or not.