Sometimes plagiarism is a good thing - essentially when the message is important but the originator was incapable of relaying the message. Here is a sampling of something not truly plagiarism but a demonstration on how a message can be delivered to a wider audience than the originator:
Both performances are strong in their own right but I would never have listened to the Dolly Parton original if it hadn't been for the Whitney Houston cover in the the movie (Bodyguard).
For my own part when I write something, I have no issue with someone copying it word for word (although I find it unlikely). While it would be nice to receive credit for the thought, the message is more important and it would be better for the message to be transferred by someone with a larger following.