The Iranian people are much different than the Afghans , most of whom dont even know how to read. These are extremely intelligent people who want more and are being held back by 11th century tyrants.
In todays world we really acnt be isolationist, its just a matter of time that whatever is out there is coming to our shore. I dont think we should get involved everywhere, pick and choose the battles based on risk/reward...
In this case It looks like the reward for both the Iranian people and to us internationally outweighs the risk. Iran is already weakened...better to do what needs to be done now rather than waiting until that government might be more of a risk.