In response to the OP, I don’t think you should take it as a trivial issue at all. The Church considers music a “necessary or integral part” of the liturgy. And it is absolutely essential that this conversation take place in charity. Parties on both sides of the debate about proper liturgical music have experienced great frustrations at times, and it is a sign of our frail human nature that these frustrations have at times clouded out the love that is meant to accompany all of our words.
An important concept to remember about the liturgy is that it is the action of Christ. The liturgy is the perfect worship revealed by God. On our own, we do not know how to worship Him perfectly. Pope Benedict brings this out in his Spirit of the Liturgy, pointing to the words of Moses to Pharaoh, who had just agreed that the Israelite men may leave Egypt, but without their wives and cattle. Moses objects, saying, “we do not know with what we must serve the LORD until we arrive there” (Ex. 10:26). As sinful men, we cannot expect to know what the Lord desires of our worship unless he tells us.
This takes particular significance with regard to liturgical music. Through the guidance of the Holy Spirit, the Church has indeed come to a greater knowledge through the centuries of right worship, through pondering upon the Word of God as revealed in Scripture and Tradition. What She proposes to us through the words of our Popes, the teaching of the magisterium, and Church documents ought to be received with the utmost reverence. The Church is entrusted with the Gospel of Christ, with true knowledge of the Father’s will.
We know, then, that our choice of music at mass cannot be reduced to a decision of personal taste. As the OP pointed out in the comments of our Holy Father, some music is of greater unity with action of the liturgy, and not all music is equally befitting of the sacrifice. In the Church’s great wisdom, which has grown through prayer throughout her 2000 year history, Gregorian Chant has been given the place of the most perfect liturgical music. The sacred music of the Church is “is a treasure of inestimable value, greater even than that of any other art,” one that “She has jealously guarded for centuries.” This has been reiterated by every Pope since St. Pius X, especially in regard to the appropriateness of any form of liturgical music, which is said to grow more and more perfect the more closely it is an image of Gregorian Chant.
This does not exclude other forms of music from the mass, but if we consider Chant as that most perfect exemplar, it becomes clear that some music is far from ideal. In all things, we must remember that the liturgy is a gift from God, and not of our own creation. In the words of our Holy Father, then Cardinal Ratzinger, “Man himself cannot simply ‘make’ worship. If God does not reveal himself, man is clutching empty space.” With humility and reverence, we should always strive to sing with the unity of the voice of Christ, the voice that we understand only through the teaching of His Church.