And just what do you think a synthetic CDO is?
Who wrote it? Who SOLD IT? And who bought it?
If you imply that CDOs were exchanged between institutional investors, including the banks, you are absolutely correct.
Have you noticed a jump: the previous statements were about the parties' allegedly causing the "mess."
If you make such startling claims, you should explain yourself. In paricular, how CDOs are related to and how they caused the mess.
Before you get into causality, you should explain what you mean by the "mess." Hint; we had more than one crisis --- the credit crisis and the housing bubble, for instance.
Rhetorical remarks "what about the air in New York" and other unrelated stuff do not help.