Why are our favorite hymns being changed?

Because you have two camps in the Catholic Church. You have the liberals, progressives, and the conservatives, the traditionalists. And the two don't like each other very much, and they have particular ways they want to worship, they want to sing, they want to build their churches, they want to relate to one another, the subjects of the world that they teach and hold on to. Oh, vastly different. But life is that way, and especially in the church for some reason.