The U.S. post-9/11 wars have forcibly displaced at least 38M people [pdf]

Any forced displacement of people is tragic.

But

1. This is over 20 years, and the conflicts of the 20th C lasted 4-7 years at most.

2. To “except WWII” from comparisons of 20th C conflicts is disingenuous. 40M refugees in Europe alone. In a 7 year war. I’d guess the Asian population displacement, that gets less exposure in the US, would be at least another 40M (surprisingly hard to find a number in a cursory search).

https://refugeesandwar.wordpress.com/world-war-ii/

WWII was a very big deal.

3. Not normalizing to world population at the time of the other conflicts is also disingenuous. Another factor of three, when comparing WWI world pop figures to today.

So, that argues for about a factor of ten adjustment down for comparison purposes and, no, you can’t ignore WWII.

Having the raw numbers by country for post-9/11 conflicts available from this paper is a real contribution.

Not to support interventionist policies (or to deny that some of these interventions have cause great suffering) but the fundamental cause-and-effect implication here is highly disingenuous.

For example - counting all 7.1 million refugees in the Syria conflict (which had its own internal roots, and probably would have played out about the same regardless of any attempt at intervention) as entirely due to a "U.S. post-9/11 war".

Although it turns out the number would have probably been the same regardless.

It's not like the Taliban, Al Qaeda, ISIS and etc were on the verge of becoming progressives.