What if instead of trying to convert people who are opposed to organ, you would go to the people who care deeply about it?
There are various groups within each congregation and there are certainly a few people who want to hear what you have to offer them.
Here's the thing: it's better to obsess and focus on these few people on the edges, your true fans than to keep trying to push that rock uphill.
No matter how hard you try, no matter how well you play, no matter what kind of music you play, they will be busy ignoring you as usual.
The flip side of this is interesting: the more value you provide to your true fans, to the insiders, the more grateful they will feel and maybe (just maybe) they will start spreading the word for you because you have figured out how to take their best dreams and lead them where they wanted to go in the first place.
Sometimes you have to be brave enough to say "it's not for you but that's OK."