The post you are responding to is probably referring to the Gramm–Leach–Bliley Act. According to some, that act (signed by Clinton) was (somewhat) responsible for the financial crash. But this is certainly a matter of dispute.
But you seem to have offered no substantial link to the existence of MBS securities and the repeal of Glass-Steagall. so your conclusion, that arbitrary deregulation, lead to the existence of MBS securities should be even more disputed.
MBS are probably more clearly linked to the complete takeover of the mortgage market by the government. if you turn debt into a commodity you can divide it up however you want. and you turn debt into a commodity by guaranteeing it.