This is not the forum for a debate on IP, but we have seen plenty of cases where data has been published, and for any of several reasons, later retracted, or altered by the original authors. Quoting in full is one way to prevent such shenanigans from happening, or at least documenting when they do. IANAL, but I feel that in some cases, the public's right to know what people are saying greatly outweighs IP issues. Especially on the types of subjects we routinely discuss here. We're talking about the very survival of our Nation in some cases.
JMHO.
TFred
P.S. One case in point that comes to the top of my mind involves the case of Gerald Ung. This law student, CHP holder was attacked by a group of most likely quite drunk LAX jock boys early one morning after a round of bar-hopping in downtown Philadelphia. Mr. Ung was forced to defend himself and his girlfriend from a violent attack, and had to shoot his attacker. Said attacker happened to be the son of a prominent Philadelphia lawyer, well connected to the local Republican party. Despite the fact that the entire scene was recorded on video, clearly showing who initiated the attack, and the fact that Mr. Ung himself called 911 to report the incident, he now finds himself facing several charges, including attempted murder. That's the long background... the point is, soon after this happened, self-defense supporters immediately found and published blog and Facebook entries of Mr. Ung's attacker, which clearly demonstrated a party-boy lifestyle and if I remember correctly, even evidence of other violent encounters. Of course, very soon, these on-line publications vanished. If they had originally been published as links only, they would have essentially never been published, as it then becomes "I saw this, but now it's gone..."