Songs take on an independent existence once they are sung in public, and the person who wrote the song in the first place doesn't have the power to be the only one to change them. Songwriters will typically change how they sing a song over the years, and that implies that the initial version isn't necessarily the last word.

Though when the changes don't seem like improvements to the person who created the song it's no wonder if they feel irritated. (If the changes do seem like improvements they are likely to be taken on board.)