Personally I have a pretty simple rule... I will not endorse or advocate any war I'm not willing to take up arms and fight in myself. And since that criteria for the most part involves whether it's self defense, I'm not seeing any reasons good enough to persuade me.
As to the inconsistent messaging, I suspect from the US government perspective this war is more about containing and/or crippling China (and to a much lesser extent Russia) than anything else. Energy is the master resource, and closing off Iran's oil exports (I think ~90% of which go to China) cuts off something like 13% of China's oil imports. Ouch. Israel's leadership has other reasons to want this, but for the US leadership I believe it's part of a larger strategy, and one they don't want to say out loud. If I remember right the ODNI's latest report said there was no significant PRESENT effort from Iran to develop nuclear weapons, so yes the whole "we had to do it or else they're gonna carry out mass destruction" excuse falls flat. To be fair to the other side, Iran's government has enriched uranium FAR more than needed for energy use, so Iran has been toeing over the line and isn't negotiating in good faith either... but still, the potential threat is not the imminent kind they hint at.
Now while I am willing to concede that there are/were horrible people in Iran's leadership and that Iran has been a threat to the REGION for decades, that is still not the same as a threat to the USA. If the majority of Iran's neighbors truly want an end to Iran's government (which seems to be the case), then that's on them. And while I do see China's government as an adversary and potential threat to the American people (not just our government), I'm not sure it's even close to the level that requires this kind of action to counter it. And even if it does, I have little confidence our "leadership" can pull it off successfully without making the general situation worse.
But at the end of the day I try to be pragmatic, and accept my opinion has zero influence on decisions made in the halls of power. IMHO we are living in an era of "might makes right" (or perhaps a better one is "the strong do what they can, and the weak suffer what they must"), and Trump and is less a driver of this change and more a symptom of the growing trend. So I try to focus less on being outraged at the hypocrisy and immorality and focus more on adapting to the developments, much like I can't change the weather but I can adapt appropriately to the conditions.