Because we’re nice people? We don’t need to cater to every person’s every whim and I do agree someone polite seem to enjoy playing the victim card. But if someone tells me in a reasonable way that they rather I didn’t wear something significant to them for fun, I feel it is polite to stop wearing that item. Call me a bleeding heart liberal or something, but I don’t like going through life not giving a fuck about other people’s feelings.
Obviously, people who cluelessly make devalued versions of songs is a pretty lightweight kind of appropriation. But it did bother you enough to notice and comment on it. In a perhaps small way, something that meant something to you has been reduced. You’re entitled to be annoyed.
I have never suggested that they should not be allowed to do so (to the contrary, in fact). I say only that you (everyone) might think of this when considering the larger and more significant (to the taken-from cultures) appropriations. The interwoven fabric of all of human culture belongs to all of us, and can make our lives richer, but only if we respect what it is, where it came from, what it means. To do less means cheating both sides of the transaction.