I just want to clear up this fantastically ambiguous misnomer again.
NO ONE who is actually serious about Catholic liturgical music and wants a restoration of it will say, “All modern/contemporary music is inappropriate for Mass.” That would be asinine. That would be equivalent to saying, “Because this piece was written in the last 100 years, it is inappropriate for Mass.” No one is trying to absolutely connect the year a piece was written to its suitability for Mass. That is simply either ignorant or unintelligent. Take your pick. There are plenty–though not exactly a lot–of Mass settings written in the past 100 years or so that are abundantly appropriate for Mass.
No one is saying that only Palestrina and Mozart and Victoria are appropriate for Mass. They, among others, are certainly the masters, but there are several modern contemporary composers who write very appropriate Mass settings. Take Dr. James MacMillan. He wrote music for the Papal visit to the UK as well as music for Archbishop Nichol’s enthronement to the See of Westminster, most (but perhaps not all…?) of which was very high quality and elicited much praise. His music is totally appropriate for the Mass, and you will do well to note that his music is anything but “Baroque-sounding” or whatever. It has clear continuity with the past, but he does do a clearly modern take on orchestral music. Consequently, it has heritage while also not sounding like it was written in the 17th century (although there is nothing at all wrong with modern composers writing such music).
My point is that we cannot judge modern music SOLELY on its year of publishing. That would be absolute folly. However, it is clear that most of what is being put out today is not appropriate for the Mass, at least not liturgically speaking. EVERY era has its sacred music and EVERY era has its junk music. The reason we are in such a term conundrum is because we speak of modern music “not being appropriate for the Mass.” This, I think, is due to the fact that we often say something like, “Baroque music is appropriate for the Mass,” or, “Renaissance music is appropriate for the Mass.” The reason why we say these things, and why they are correct, is because generally, low-quality music of such eras does not survive to this day in common use, and so we can use a broader brush when using the terms. However, we cannot use such a broad brush with modern music because we live in the modern era, and as such, we have various qualities of music that all endure, because it has not been long enough to “weed out” the low-quality stuff.
THEREFORE, I posit that we use new, more precise terms:
“Contemporary sacred music.”
This term would be used to describe music by such composers as Dr. Macmillan and Kevin Allen, to the complete exclusion and discrimination of pop- or hymn-type music, which we can call:
“Religious music.”
The difference between contemporary sacred music and religious music being that the former is specifically intended for liturgical use, and the latter is intended for unofficial actions/devotions/parish get-togethers/whatever else of the Church. The former will be, in the words of Pius X, “excellent, sober and grave.” The latter will have more liberal allowances, in that it can be of almost any style and quality as long as it is not sacrilegious.
Of course, I am open to refinement of the terms and their definitions, but can we agree basically?