I wouldn’t expect an extremely old person to be aware of all the nuances of modern language. Least of all the pope, who, I’d assume, has effectively zero contact with anyone even remotely close to being a rainbow activist. External culture and langue has moved a lot in the last 15-20 years. While I am far from that old, it’s not unreasonable to expect that calling someone that was relatively normal during the popes childhood, certainly in a religious environment.