"The probelm with the internet is that you can't always tell whether the quotes are accurate." - Abraham Lincoln
LOL, that was Samuel Clemens referring to how his alter ego Mark Twain was misquoted on the internet.
Seriously, the point is a good one. Arguments based or supported on incomplete, manipulated, misworded, or otherwise incorrect quotes are arguments that are not well based or well supported by such quotes and they make the person passing off such errant information appear to not comprehend what s/he is talking about, even if the goal of the citation was noble. One can get by with the gist of quoting via paraphrasing, but the paraphrasing needs to be inclusive of the correct content and intent of the original quote in order to be appropriately applied or it is no better than incorrect quoting.
Of course, this also applies to actual data that is often bantered about.