Let me be the first to suggest that there will be an Imam there...
He might not have an imam speak, but he thinks the cost of eliminating this possible source of controversy is that nobody can speak in the context of faith. I’d rather the imam be allowed to wail in Arabic to Allah whatever he wants, and that Christian, Jewish, Buddhist, whatever clergy who wish to remember the fallen be invited to speak their own pieces. After all, Muslims who knew nothing of the terrorist attack perished in the towers. People can hopefully keep their peace if an imam remembers those victims out loud.