iTunes is really trying to clean itself up after years of complaints about people buying a song only to find out it's a tribute or cover, or even worse, a cover by the real artist. Many artists re-record a track in order to cut the record company out of the royalty pipeline. It may sound close, but it's not the original and usually you can tell.
The latest iTunes Style Guide (here's a link to the previous one) apparently says that track titles that state "Originally performed by," "In the style of," "Tribute to," or "Cover of" will be automatically rejected. Also, any songs that violate these guidelines that currently are on the library will eventually be taken down.
Karaoke and instrumental versions are the exception, however, as long as they're placed in the correct category.
iTunes will also no longer accept titles that include popular song lyrics either.
This problem is more acute on digital download services where you think you're getting one thing and instead pay for something else. With a streaming service you just move on, trying to find the version that you want, so they don't have the same restrictions in place that iTunes has.
