https://www.breitbart.com/faith/2022/03/16/pope-francis-tells-russian-patriarch-all-wars-unjust/
“At one time there was talk in our Churches of holy war or just war,” Francis said. “Today we cannot speak like that. The Christian awareness of the importance of peace has developed.”
“Wars are always unjust,” he continued, “because those who pay are the people of God. Our hearts cannot fail to weep in front of the children, the women killed, all the victims of war.”
“War is never the way,” he said. “The Spirit who unites us asks us as pastors to help the peoples who suffer from war.”
In contrast, Aquinas discusses conditions under which war may be justified in his Summa:
https://www.newadvent.org/summa/3040.htm
I answer that, In order for a war to be just, three things are necessary. First, the authority of the sovereign by whose command the war is to be waged. ... Secondly, a just cause is required, namely that those who are attacked, should be attacked because they deserve it on account of some fault. ... Thirdly, it is necessary that the belligerents should have a rightful intention, so that they intend the advancement of good, or the avoidance of evil.
Other Catholic theologians have weighed in on the topic to form "Just War" theory about when war can be justified: https://infogalactic.com/info/Just_war_theory#Christian_views
The Crusades themselves were military campaigns "sanctioned by various popes": https://infogalactic.com/info/Crusades
It would have been sufficient for Francis to argue instead about certain wars being unjust, or lament the horrors even of a just war, rather than erroneously promote the view that all wars are unjust, which is contrary to Catholic teaching.