So your theory is that the US government giving incentives for companies to make loans and sell them off didn't contribute to problems? Especially when combined with the actions of the Fed. If your argument is that Fannie and Freddie weren't the sole cause, then I'm with you.
I don't know enough about Canadian law to comment on Canadian banks, but the meme that US banks were thoroughly deregulated is...delusional. In any case, as the GP pointed out, it was the US, through regulators and others (yes, including Fannie and Freddie!), that was encouraging the risky behavior of the banks.
Booms and busts are basically a natural thing in biology and economics. But that doesn't mean we need governments providing perverse incentives to make them worse.