"Nope, poverty exists because people don't get heterosexually married." Where did he say anything even close to that, & why are you bringing heterosexual marriage, specifically, to a discussion that didn't include gay rights?

All the factors mentioned in your 2nd paragraph impact those who choose to follow the sequence of high school diploma, marriage, then children. Yet statistics show those specific choices differentiate those who are able to overcome those issues and those who don't. 

As for "poverty is people's own fault" - poverty doesn't magically reach out & slap all poor at random. People who are in poverty make choices throughout their lives, just as people not in poverty make choices. Some choices are going to lead to better outcomes. Applying oneself to school, avoiding friends who drink, use drugs or commit crime, and pursuing a profession, whether through college or other formal training, will have a higher likelihood of a better outcome than choosing the opposite.