Conservative Muslims preach "Death to America".
Conservative in what way?
They have been radically aggressive in search of influence and territory since the fall of the Shah.
Conservative in that they foster much less violence and chaos than many other states in the region and than those that would likely benefit from their downfall.
Every time you meddle in the region you make things worse, if Carter hadn’t decided to meddle the Shah would still be there instead of the current regime.
Iran’s responsibility in the Beirut massacre and IEDs in Iraq and Afghanistan is enough to eliminate the regime at a time of our choosing. Imagine a Iran without the Mullahs or imagine a nuclear Iran with psychotic Mullahs who wish for the 12th Imam.