Last night I attended a small local monthly open mic night. One of the performers was a preacher. He sang two religious songs. I couldn't help but roll my eyes but I did clap for his performance. I think it would have been rude not to. He gave me a creepy feeling though with the way he carried himself. His voice filled the room without the use of a microphone. It was as if he knew the power his voice had.
Gospel music has had an enormous influence on modern music. It's ok to like it. You won't be contaminated. ?
Yeah, music is music. I've often enjoyed something just to find out later its religious overtones/connotations. I try not to let preconceptions influence my enjoyment.
It has a lot to do with confidence and technique. I can fill a room without a mic because I used to busk without one. Opera singers do the same. Try singing something like "Mercedes Benz" on the way home from the pub. That will improve your volume if not your relationship with the neighborhood.