I agree with you, but I daresay don’t even try to argue with any of these folks, they think they are better than the rest of the schlubs who find anything worthwhile with any of this so-called crappy music.
Many people like the songs you have mentioned and there’s absoutely nothing wrong with singing them in church - but just NOT in a Mass. They’re not liturgical songs.
They’d be fine for, say, some kind of prayer service, or perhaps to preface the parish Bible study program, etc. But they’re overly personal and overly sentimental for use in a formal liturgical setting. Furthermore, many of them are actually soloist pieces and would sound much better if sung by an individual with the appropriate accompaniment than droned through by a congregation.
Something that sounds great when sung by Cristina Aguillera is not going to sound great when sung early Sunday morning by a roomful of people mostly over the age of 60. And I have noticed that men frequently refuse to sing these songs at all, probably because the words are so emotional and feminine.
So I don’t think people on this thread are condemning these songs, but instead are simply complaining that they don’t “fit” in the Mass. In the 19th century, Church authorities had to weed out many operatic-style songs that did not fit with the Mass (and it was the old Mass, too!) and some of the songs are still popular and still with us today - but not in the Mass. This is the same situation.