Why USA not listen Ahmedinejad?

Ahmedinejad of Iran is voicing loud to have a roundtable discussion with the USA president Obama on how to better lead the world. The response to his call is, however, deaf ear. Why should not USA (Obama) give a chance to Ahmedinejad to listen what he says. A good point can be gained even from a mad!

It is not good for USA to make nations bow down for her through force. Even along with force, any discussion (diplomacy) invited by any nation should not be rejected. It is alleged that Iran is sponsoring terrorism. If that is the case, should any invitation for discussion by allegedly terrorist supporter be rejected?

In my opinion, terrorism can never be abolished by force except by diplomatic means and trying to be nearer to the terrorists to even understand what they are seeking from the world. It is after understanding their core demand and mission that compromise can be arrived and terrorism ceased. Is that not?