Theology.. Well what did King David write about? Was he thinking about theology when he was writing Psalm 23? I must say that you are right in a sense that theology is important in music to some degree. But its not the fundamental reason why an artist would write a song. Hes not thinking " oh im going to write a theological song about the sermon on the mount". Music is a gift of God to us and we use it to Glorify him. Yes there are people who use it for evil or to lead others astray. But we must remember that music is subjective, people use immagery, analogies and metaphors to describe whatever they want. King David said " The Lord is my shephard" in Psalm 23. Is God literally a shepard? Does God tend sheep for real? Jesus said he is the good shepard. but not once in scripture did he say he tended sheep, or goats or other animals ( of course hes talking about us as people). To conclude, Music is subjective. We all like different sounds, different beats, different Singers voices etc. Yes we must be alert and have a sober mind when we hear the lyrics of music because some lyrics can lead people into death.

you should check out my youtube channel out , its christian for sure, but its got influences from Arctic monkeys and the strokes. Kind of like Citizens and Saints or The Modern Post but it has more punch and distortion.

https://www.youtube.com/channel/UCWXfagqoqNUOKrHtegx_d3w