I have repeatedly had people on the US right explain to me that the 2008 mortgage crisis was due to government-mandated loans to poor people.

As an example, here's some 2008 discussion of this thesis: http://www.slate.com/articles/business/moneybox/2008/10/subp...

Here's a 2016 discussion of similar themes: http://ritholtz.com/2016/06/no-cra-not-cause-financial-crisi...

That never matched my understanding, but it was practically an article of faith for them.