He's right.
We cannot be in the business of reading the minds of foreign leaders, such as the latest Iranian Ayatollah. We certainly should not be pretending to read their minds and giving the reading the most optimistic slant possible, i.e. that Iran just happens to have all they need to build a nuclear weapon, but they certainly do not intend to build one.
Whether we should have participated militarily in stopping Iran from having the capability to make a nuclear weapon is a different question. You could make an argument that letting Israel carry the ball while we only provide the ball would be a better way to stop the nuclear program in Iran.
Or you could argue that no one should tell Iran they cannot have a nuke.
But it is pretty naive to say "unless they say so, there is no reason to believe that Iran wants a bomb."