see this is what you do when you wish to reply specifically to another poster's comment without having the thing spread out all over the page, and the comment in question is not particularly relevant to the discussion.
it's called snipping.
it allows you to direct your comment to the appropriate target without having 400 yards of redundant posts.
this saves server bandwidth and file space.
people over the age of 30 do this because once upon a time overly repetitive posts would become brobdingnagian monstrosities that took half an hour to download via a 1200 baud modem.
it's usually viewed as polite. unless the commentary is derogatory as mine was.
sometimes one has to express one's opinion with a sideways insult to the supposed intellligence of the other poster.
no-one not even yourself believed that i was "quoting" you, or attempting to put words in your mouth.
anyone who believed that would have to be clinically retarded.
pretending to believe that is somehow even worse.
the sort of behavior one might find among drama queens fighting for attention.