The 'excuse' for mixed choirs is that TLS is no longer in force.

5. The Church has always recognized and favored the progress of the arts, admitting to the service of religion everything good and beautiful discovered by genius in the course of ages …

6. Among the different kinds of modern music, that which appears less suitable …

I'll readily grant that Pius X knew it when he saw it.

Not so much on the grounds that choirs of men and boys had never existed in America: they had indeed, in a few places. But the question went to Rome asking for permission to continue mixed choirs, and included (as one reason) the fact that in most places, even in cathedrals, they were in practice the only choirs in existence.

After Tra le sollecitudini appeared, there were questions to Rome from both bishops and lay organizations (including the journal Church Music). At one point, the wording of the directives from Rome even seemed to prohibit women from singing in the congregation, though this was contrary to the Pope's wish to encourage congregational singing. The eventual reply (published in that journal around 1908-09) was that the prohibition against mixed choirs wasn't going to change, but that if men couldn't handle the singing by themselves, then at least keep the men and women physically separate for the sake of propriety.

I wonder if MBurrier would find this compelling at all?
https://www.youtube.com/watch?v=kmWs94KbiJQ

I wonder what Church documents Mburrier has read or studied about sacred music in the Church?

To MBurrier,

I rarely post but read this forum with regularity. You accuse people of being "qua-school marms" and Pharisees and Sadducees ( quite the cliches) and gate-keepers and people who pursue dead-ends.

However, you have not engaged anyone here with anything except ad hominem arguments, name-calling and labeling. You have not made one iota of an argument for your position except through these labels and ad hominem responses. You do not support any statement of your own. You cannot cite documents or articles. You cannot deduce any compelling reason for your statements other than "its my way" or "my taste", which does not hold up in any argument on the merits of the choice of music for the liturgy.

I will not stoop to your depth of uncharitable thinking. But I would suggest that you do not act in the manner you wish others to act. That is to say, civil discourse or reflective thinking and cogent argumentation, which has a fine and marvelous history within the Church.

The profession of Roman Catholic Church musician is an honorable one. I know that as I have served 36 years in that capacity. I am an organist,choirmaster, lover of chant and choral music. I regularly teach young children the glories of chant, polyphony and good singing. My students adore and love chant, because I share with them my joy and love for it and the Church in general. I respect all my colleagues who do this work, knowing full well that we don't always agree. We argue,cite documents and learn from each other.

The arguments you foist upon this forum are not supported with anything except your own force of labeling,ad hominem and name calling. They are not the tools of civil discourse. I invite you to civil discourse without the ad hominem responses. I pray you to act in the Christ-like manner that we are asked to do...in this place and in life.

Those whom I deeply respect here deserve such a grace-ful response.

@mburrier - that's helpful background. Some of the music you are advocating for may well be appropriate in Catholic worship, but not in Mass. Catholic liturgy as it now commonly exists is not what many here think it ought to be. In particular there should be far more liturgy in Catholic churches than just Mass, even if in various styles. Mass is only one part of the church's liturgical riches, and the other liturgies and para-liturgies have different focus and require different music. There is a rich repertory of Catholic hymns extending over at least 1500 years, but until the last few decades they were not written for Mass, and indeed were explicitly excluded (that's over simplified). Catholic churches should have 'campfire Jesus songs', but in non-eucharistic services.