As an ex-church organist I was given one tip when starting out.

Ignore the congregation. Set a reasonable pace - not racing and not dragging - and keep to it. They will catch up - they even prefer a good pace - no-one really likes the ever slowing down dirge pace...

This ever slowing down pace is caused by the organist listening for the congregation to respond to the played notes - because of distances in a large church the audio delay is noticeable.

Perhaps similar things can be happening when folk music gets slowed down...