Maybe this is my simple interpretation. You have shared info you are nationality X. Twtr knows that outrage fuels engagement. Content Y allows for this to happen, and increase retention based on what others who are X have reacted previously. Perverse incentives.
Or even glanced at something once in trending without giving it much thought..
I haven't shared my nationality. But they sure have my IP. Maybe it's not war-fueling; maybe it is "just" engagement farming. Regardless, it's hideous.
IP, and phone number + country code, and preferred languages on your device, and languages you search in, and languages of notes you look at and translate (or not) etc. Nationality/related interest seems trivially inferred.
No phone number. Everything is/in US English. Notes I look at are 99% in English as well. Only IP.