Should we have not stopped ISIS? I’m not trying to be funny btw.
This framing of the question creates the exact same kind of tunnel-visioned compartmentalization that leads to forever wars in the first place. In the real world, it never actually "stops".
The USA justifies all the violence in Iraq cause, as you say, they just had to "stop" Abu Bakr al-Baghdadi and ISIS, though al-Baghdadi had only been able to come to power and bring Isis to its greatest heights because the USA just had to "stop" Abu Omar al-Baghdadi and Abu Ayyub al-Masri, who themselves had only brought Isis to the role of dominant insurgent group in Iraq when the USA made sure to "stop" Al-Queda-in-Iraq by killing
al-Zarqawi, who himself had been able to form the group solely due to his presence in US occupation prisons and was in a position to arm the group due to the violence we brought cause we just had to "stop" Saddam, who himself was armed in the midst of the violence we brought cause we just had to "stop" Khomeini, whose power was created in the midst of the violence we brought cause we just had to "stop" Mosaddegh....
Just like the power of the Taliban and thus Al-Queda in Afghanistan was created in the midst of the Afghan civil wars which were the result of us arming a lot of despicable people cause we just had to "stop" the Soviets, who of course had been our former allies who we happily helped fight (eventually increasing their global power for several generations) cause we just had to "stop" Hitler, who of course gained power as a result of the repercussions of WW1 when we just had to "stop" the Germans.
Pol Pot got his power cause we decided that Sihanouk was the bad guy and we had to get rid of him.
Isis and the other warlords and terrorists of Libya gained their power cause we decided Gaddafi was the bad guy and had to get rid of him.
Mobutu came to power because we decided Lumumba was the bad guy and we had to get rid of him.
Banzer got power cause we decided Torres was the bad guy and we had to get rid of him.
Castro got power because we decided Socarrás was the bad guy and we had to get rid of him.
Pinochet got power because we decided Allende was the bad guy and we had to get rid of him.
The ugly military junta that rules Myanmar to this day is there in part because we felt the Chinese communists were the bad guys and thus supported the Kuomintang campaign in an effort to get rid of them.
Ethiopia and Eritrea. Angola. Damn near every nation of significance in Central America and the Caribbean. All saw violence come to their nations downstream of renowned American leaders supporting violent conflicts in their nations which led, predictably, to even more violence.
The point of all that is that American powermongers have shown that they have for-shyt ability to project the future implications of their violent actions or predict whether their violent actions will "stop" violence or in fact create much more of it. Sometimes we kill a few violent leaders (and a few thousand innocent civilians in the process), and get a period of relatively more calm in the follow-up. Sometimes just the opposite happens. We never appear to substantially rethink whether the ugly track record of our interventions and questionable moral authority in carrying them out might lead to more long-term harm than good. Instead we're continuously caught up in the present moment. The USA has the most powerful and capable force for violence in world history, and when you have such a fantastic hammer, every problem looks like a nail.
At what point do the unintended consequences amount to enough suffering that you will at least consider whether there may be some other, better way?