There's no comparison at all. When the Pope says that abortion is wrong, he is speaking in union with 2000 years of Church teaching on a matter of faith as morals. He is speaking in union with biblical teaching. It's as straightforward as saying that murder is wrong and stealing is wrong.
To the contrary, the question of whether or not a particular war is justified is a matter of "prudential judgment." There is a recognized right of self defense, and a recognized duty for a head of state to protect his people. Unlike some Catholic figures, the Pope has never said that this war is wrong and has never even come near telling Catholics that they must think it is wrong.
You have a very superficial picture of the Catholic Church.
Oops! Sorry about that. On behalf of all those who take the pope seriously, I most humbly apologize to the I'm-an-American-first Catholics who most obviously know better.