It's a decent movie, but it omits Bill Clinton's role (the cause) in the GFC, specifically his National Homeownership Strategy.
When you push for more easily accessible credit for those who have an increased probability of being unable to pay it back... bad things happen. Worst of all, there was even more than just the issuing of subprime mortgages. A lot of people might take away the corruptness of the bankers, regulators, etc. This is known however, people will always try to exploit the 'system', especially when you abstract away from the morally dubious nature of their actions (taking money from an elderly ladies pocket is different from say exposing a large sum of money, part of it being her life-savings, in a financial instrument that has a triple A credit rating...). This type of behaviour or corruption should be expected, it is a given. People shouldn't be upset that humans are sometimes bad or stupid, that's a given, they should be upset about the government policies that allow situations like this to occur. You might categorize what happened as an 'unintended consequence', but really it's quite an obvious consequence, and if Sanders get's elected, ya'll will really 'feel the bern' when down the line these 'unintended consequences' materialize.
I really did find it unfortunate that the movie didn't mention what caused mortgage brokers to lax their standards, maybe then more people would've realized that your parents were right in saying that: "there's no such thing as a free lunch".