We're living in a world where the former president of Iran is quoting Tupac and the president of the United States is quoting Walter Headley.
Ahmadinejad addressing americans is always weird. It doesn't make sense as propaganda, because it's not like public opinion has much effect on US foreign policy, and it's not like there are many people outside of government who are both able to point out Iran on a map and think antagonizing it is a good idea. I'd almost believe he's sincere just because I can't think of any other reason he'd bother.
I'm no foreign policy expert nor middle east wonk. But my understanding of Ahmadinejad is he was basically the figurehead the Mullahs pulled in to purge Khatami and his people when George W Bush came to power, and then pulled out when it looked like maybe they could work with Obama. I get the sense that he didn't like being sidelined.