The key difference here is that one group is going after those they consider guilty of unauthorized copying of media, while the other is simply trying to have their claim of authorship respected.
Torrent files of MP3s and TV shows don't, as a general rule, mis-represent the original creators of a work. Because of that, they can still drive real revenue for those artists -- people may initially acquire an album or episodes of a TV show illegally, then go on in the future to pay for new content from the same people.
Doing a copy-and-paste job on someone else's blog content, however, breaks the link (however tenuous) between author and reader, which means that the author is unlikely to ever see anything of value back from the interaction. Not only are they deprived of direct financial (AdSense) and social (search rankings, public visibility) benefits, they are robbed of one of the most valuable commodities available to a blogger: direct feedback from interested readers.
Torrent files of MP3s and TV shows don't, as a general rule, mis-represent the original creators of a work. Because of that, they can still drive real revenue for those artists -- people may initially acquire an album or episodes of a TV show illegally, then go on in the future to pay for new content from the same people.
Doing a copy-and-paste job on someone else's blog content, however, breaks the link (however tenuous) between author and reader, which means that the author is unlikely to ever see anything of value back from the interaction. Not only are they deprived of direct financial (AdSense) and social (search rankings, public visibility) benefits, they are robbed of one of the most valuable commodities available to a blogger: direct feedback from interested readers.