"Borrowing" music

I have always been a huge fan of Elvis Presley. My parents love his music so I grew up listening to him. However, I was very surprised to learn that he "borrowed" his music from African American musicians. It made me see Elvis in a completely different way, and it made me almost lose respect for him in many ways. I agree with a previous post that a song should be written by the person who performs it simply because it makes the song more genuine. I think that cover songs are the closest thing we see to this today, but covers are often good because they make the song popular again. Glee is a perfect example of this. All the songs the cast performs are covers and I think that it is opening the songs up to a younger audience who wouldn't normally listen to these songs. Obviously, the major difference between "borrowing" songs and cover songs is that the artists are paid royalties. It is very sad that African American musicans weren't even acknowledged as the creators of the songs, and that audiences just assumed that the person performing the song was the composer or lyricist. It makes me wonder how many other famous songs were stolen from other musicians who were never given credit.