Some people (and congregations) are totally clueless about traditional hymns, chant, etc. If they like the sentiment of a particular song, and if it sounds like the music they listen to outside of church, they will think it’s “good” music. So, if they are presenting mediocre music at Mass but sincerely believe it to be “good” music, and are putting forth their best efforts, I think God is certainly pleased. And if they are presenting excellent music but even their best efforts are pretty weak, I think God is pleased with that, as well, as long as they are trying their best. (I surely hope so, because that was my situation when I first returned to playing the pipe organ! Weak skills but sincere performance, until I improved enough to sound decent).
OTOH, if they DO know better, but continue to use exclusively mediocre music simply because it’s easier, perhaps God is not so pleased with that – not so much because of the music itself, but because of the lax attitude and the failure to strive toward excellence. However, doing a makeover of a particular parish’s music is not an easy task, and usually must be undertaken slowly and gently.
One thing which I am sure is
not pleasing to God is the amount of fault-finding, prideful attitudes, and backbiting which so often goes on behind the scenes in so many church music departments, and sometimes from the congregation as well. And that can happen whether the choir is singing pop-style songs or Gregorian chant.