In this case you're assuming that the current status quo is "good".

Absolutely not. That's why I keep reciting that fallacy to you. To show that even when the status quo is bad it does not mean that any specific which changes the status quo should be done. That's the fallacy:

1. Something must be done.
2. This is something.
3. Therefore we must do this.

In those terms, you can see why it's flawed logic. The fact that something has to be done - that the status quo needs to be changed - does not mean that any possible thing that you can do must therefore be done. There is a universe of possible things that can be done - and the fact that something must be done does not mean that any specific one of those things is a thing that must be done.

That's why it is possible that it can be true that both: i) the existing situation with Iran was bad; and ii) attacking them this way was something we shouldn't have done. Just because the second proposition is true doesn't mean that the first proposition is false.

Similarly, it doesn't matter how many times someone points out "Something must be done!" - it doesn't necessarily mean that any specific course of action is the thing that must be done. Pointing out over and over again how bad it would be for Iran to get a nuclear weapon doesn't necessarily mean that any particular thing we might do is therefore something we must do. Again - "something must be done" doesn't mean "therefore we must do this" for every single "this." Only some "this" should be done, and some should not - not matter how much the status quo must change.