They're referring to the
Community Reinvestment Act among other things. Under Clinton, lenders were required to lower their standards a little for designating a loan as "sub-prime". Because lenders are greedy and dumb (but clever enough to realise that no matter how crappy their assets were they could still offload them on other suckers) they all went crazy trying to give out more and more worthless loans in order to keep up with each other in the bonus race.
Now, I hear there are rules in place that [seem to] say that lenders have to give loans to anyone who wants one, but there is in fact no rule in place that says "you can't inform the prospective loan-taker that this is a very bad idea and they're likely to default on their loan because he's poorer than he thinks and this loan is waaaay tricksier than he thinks". The option was always there for a banker to tell the hopeful sucker who wanted a loan that it was a bad idea, but what banker would do that? Turn away free money? Fuuuuck.