I'm not sure why the parent doesn't like it, but I can explain why I don't like it. I think there's a certain group of users who have developed the habit of highlighting while reading to keep their place in scrolling media. At least, that's why I highlight text a lot. For me, the quote box is annoying, but I can see how it might be useful for people who don't highlight text while reading.
I am also one of those who highlights while they read and find this quiet annoying. There seems to be no real reason for the button to start at your mouse pointer and move over to it’s final resting position. Just showing it in its final resting position would decrease the obnoxiousness of it ten fold.
Some folks really enjoyed <blink>, <marquee>, and auto-playing MIDI songs.
I'm not saying those opinions are unimportant, but maybe features that resemble <marquee> would be unpopular for reasons similar to why <marquee> became unpopular? ;)