Paintings have many parts. The art of the painting contains line, color, shape, texture, etc. When observing a painting it can also be helpful to understand what was going on in the life of the artist at they time they painted it. Why then do we treat music any different than other forms of art, such as paintings?
I think we should be cautious to label music “Christian” or “Secular.” Music has line, color, shape, and texture just like any other work of art. What do the words communicate? What emotion does it evoke? What associations are made in your mind? If these things dishonor God, then we probably shouldn’t listen to it . . . at least not without an extremely protected mind and heart.
God made music, and he made it good. Many people pervert it into something it isn’t. But I don’t think that means we should completely ignore any music that doesn’t have “Jesus Saves” on the front cover.