I don't mean to take sides or anything in this matter, but there was a very similar backlash that Firefox faced a few years ago. I really appreciate all of the work that's gone into Calibre, and I use the Arch Linux package (where I don't remember seeing any EULA-style dialogs), so this matter doesn't really affect me, but I figured I'd at least post some of the relevant links. In the end, though, I don't think Firefox displays the GPL on first boot.
https://bugs.launchpad.net/ubuntu/+s....0/+bug/269656
http://blog.lizardwrangler.com/2008/...icense-issues/
http://www.groklaw.net/article.php?s...80917045510597
http://www.groklaw.net/articlebasic....80919113727960