See my "democracies are better" thread. I reject your attempted moral equivalence between Iran and proper nations.since we simply cannot prevent them from having weapons and we need a rule or philosophy to prevent this, we simply cannot base our rule on such a subjective term like "state sponsor of terrorism".
Transgressions by democracies can generally be addressed by media pressure--as I recall it got pretty sticky for a bunch of politicians when it came out they were supporting the contras. I don't think that went well for them. In the case of dictatorships and authoritarian regimes it seems that media pressure generally has little effect, it requires military intervention to get them to back off.