I wouldn't say it's unreliable, just very biased...
I tend to not believe that heavily biased news sources are reliable. It is inevitable that the bias affects the choice in what information is given and what interpretation can be made from the information, making the message unreliable.
No. A site can be selective in what it reports and yet report truthfully. You have to use such sources with care but that doesn't make them false.
In this case it's simply posting somebody else's work, the credibility or lack thereof of the site is irrelevant unless you're saying the material is faked. (And since they posted a followup on their own site I think this is very unlikely.)