I agree that applause after mass is inappropriate. I also believe, though, that most congregants are well-meaning and just don’t realize that it is inappropriate. It’s difficult for the musicians to tell the people that shouldn’t applaud. I’m a cantor and soloist and it’s very embarrassing when I’ve been applauded. Those people are very appreciative, so I think it would be equally rude of me to say to them over the mic, “I’m sorry you should not be applauding me. I’m doing this for God.” I think what would be best is if the pastor puts something it in the weekly bulletin regarding applause every week or maybe place it in the announcements prior to mass. I know at our Cathedral, the choir and organist get applauded A LOT. They do excellent choral and organ compositions for the high masses. Most of the congregants are visitors from other cities and countries and many have approached the musicians complimenting them and thanking them for music they usually don’t get to hear at their parishes. Our organist is probably the best in the city and I can safely say he can outplay almost anyone with his musical abilities and genius on the organ and the piano since he is classically trained as a concert pianist as well. But he also does not want applause because he looks at the music as a prayer, not a performance. Many times he is jolted out of his prayer and meditation at the end of his playing when the clapping occurs.
The thing is, too, most church musicians are not doing it for the applause and glory. Once the applauding becomes the norm, some people think that this is what the musicians want (it usually isn’t) and that they are showing off their talents (that is also usually not the case). It gives musicians a bad reputation of being “attention whores”. I’ve seen this happen to some of my colleagues and it wasn’t fair to them and the more talented they were, the worse the assumptions.
If a good musician wanted to “perform” they would do performances outside of church - which is what I and many of my colleagues do. I don’t actually “perform” when I “perform” in church.

I’m actually praying, but using my singing voice or whatever other instrument to pray. It’s sometimes hard to separate the perfectionism of a musician from the pure spiritual aspects of music, which is why spiritual meditation before singing is very important for me.
Anyway, those are my thoughts on it.