Why confront Iran?
Iran was working on all the non-nuclear components of a nuclear arsenal. That violates the spirit of the nuclear deal.
Why can't Iran have nuclear weapons?
Asking this question is a little like a Jew in Germany in 1933 saying Hitler doesn't mean it when he says there is Jew problem. How many times does Iran have to say "death to America" before people believe it? In the age of nuclear missiles, waiting too long to confront a problem means you get to die.
But Iran only says death to America because of America's behavior.
If you believe that people are basically good, like Obama does, then so are countries. This idea flows from "equality." They only misbehave when somebody else (read US or Israel) pushes them too far. Hence, the blame for Iran lies elsewhere.
What if people and countries are NOT basically good?
Mark 10:18 And Jesus said unto him, Why callest thou me good? there is none good but one, that is, God.
Look who thought people ARE good:
Anne Frank: "Yet I cling to them because I still believe, in spite of everything, that people are truly
good at heart."