What has Christianity truly contributed to humanity

[Thumpalumpacus]

It's not "fair". You obviously don't know any church musicians, and me, I know too many.  

You're wrong here. My mom, who turned me onto Bach in the first place, played organ in her church from eleven to eighteen, when she married. And having myself sang choir in church as a youth, I knew pianists, organists, and guitarists who played for services. This is you trying to chest-thump when you don't know your ass from third base about your interlocutor.

You should probably limit yourself to posting about things you know about, but that would likely amount to a self-ban.

He needed a piece, found a text, (or was given it), and wrote it out. Your assumption is totally unwarranted. 

Wait, my assumption is that he's just writing his upbringing. You're assuming his Christian faith had nothing to do with it. So we both hold assumptions, but I'm pretty sure mine stand on steadier ground.

He needed something to fill out a service, just like countless others.
I might not doubt his faith, but I know of no reason to assume his work-product or even occupation was in any way the result of any "faith".

So I'd asked you for any sources, and you clearly have none, else you would present them.

Why is a Lutheran writing Catholic masses ?

It's almost like you're ignorant of the fact that Lutherans hold Mass as well.

This is a Bucky-can't-be-wrong moment, rather than you just simply listening to an opinion that doesn't agree with yours. I'd feel sorry for you, but you're making your own unhappiness by not being able to listen.

Thankfully, that's not a me-problem.