Okay, it's a little over the top for Sarah Palin to accuse her critics of "blood libel." But she does have a basic point. She had nothing to do with Jared Loughner. He was not an extremist who embraced some radical version of her ideas. And her use of targets to identify districts Republicans were, um, targetting is not exceptional or prone to incite anybody.
What's happening is that Palin has come to represent unhinged grassroots conservatism, and people in the media immediately (and incorrectly) associated Loughner with the far right. Moreover, the Republican establishment understands her potential candidacy as a liability and is looking to snuff it out. So you have this weird moment where Palin is on trial for something she has no connection with at all.