Trading instruments like mortgage-backed securities does not constitute "gambling with people's homes." It's not like someone's taking your home away just because of some CDO trades.
"Activist investing" (think Icahn) might, albeit indirectly. But that certainly doesn't make up a big chunk of the market and its activites.
I'm not saying that the GFC wasn't massive (it was) or that people didn't lose their jobs and homes (many did), but MBS were not at fault. Subprime lending was, among other factors.
Arguably the originator banks deserve a lot more blame for that, since they actually were the ones willingly handing out bad loans and/or encouraging bad consumer practices.
Answer: unemployment went from 4.6 to 10%, and it took eight years to recover: http://infographic.statista.com/normal/chartoftheday_8974_us...