it doesn’t matter if the Holy See doesn’t say a way is just/unjust. Its not the Holy Seas job to do these things. It is up to the individual leaders of countries to go through the steps of just war and see if they can fight, not up to the Pope to be the moral police of all the countries. While men of the government aren’t very morally founded in Christian doctrine they are still capable for making decisions on Wars themselves and the Church shouldn’t get involved in it.
The Church has said that abortion is immoral in all cases, but you never here the Vatican coming out and saying law x should be voted against, Why? because its not their job to make those statements.
What the Church has done is given the faithful a moral code to live by and specifically when it comes to War it has through Augustine and Aquinas the Just War Doctrine. The Church has nothing more to do on this matter she has spoken to what she needs to speak to. Its up to the faithful to follow them.
So while the Vatican doesn’t really say much when it comes to just war or unjust war. The local church talks about it all the time because they are the ones who have an impact on the decision of war, not the Holy See.