What does it mean to respect a piece of music? Does respect mean treating it the way one treats a person? Do the same kinds of values matter when one is in relationship to an artistic creation as to a human being?
A good deal of what would constitute respect is connected to knowledge. You have to have some kind of information before you can be respectful. Without it, you might be disrespectful and not even know it. That could be a problem. The knowledge would probably be some kind of context for the piece of music — where did it come from? Who wrote it? When? Why? What else was going on at the same time, both musically and in the world at large. What is known about the composer and/or lyricist? What is known about the style of music in which the piece is written, and the style as it was or is represented by other composers of the same era? What is known about the composer’s intentions, based upon how it was done originally, or anything that has been written about the piece?
Artistic license says that anything is possible, but we do have to get permission from a composer and author of a published piece of music before we change any of its written notes or words, unless the changes are very small. If the piece is changed so much as to become unrecognizable, it can be considered to have been destroyed. This isn’t artistic license, it is criminal, and can be prosecuted in a court of law by the copyright holders.
Therefore, when someone is arranging a song for a jazz artist, for example, the arrangement can be creative and unique but the arranger cannot re-write the song. Knowing how far to go is a judgment, usuallly made by someone wise enough to have been around the music world long enough to know by exposure what appropriate musical and artistic boundaries are acceptable.
Taking a song completely out of context can certainly constitute disrespect. Not liking certain styles of music but performing them anyway, is disrespectful. Squeezing certain songs to fit one’s own limited ability to sing is also an abuse. (That’s why taking a gospel song and singing it with an operatic or classical sound is repugnant. No matter how schooled the singer, any music is not “improved” by changing it’s character because the vocalist has only one way to sing it).
One of the most amazing attitudes to encounter amongst voice teachers is that of profound ignorance. Teachers of CCM who don’t even have the minimum amount of information about any style of CCM to know that they are being disrespectful to these styles abound. This only matters because the music deserves to be respected. We’re still a long way off from having this be the gold standard in terms of training and performance.