How much "copyrighted" Material is cut and reposted on FR? I think the courts need to weigh "intent". No one here intends to rip off printed media.
Before even the courts weigh intent, first the companies will. In 99% of the cases (obvious estimate) of material being posted on FR, no claim is made. In the few cases of when that happens, such as the liberal leaning websites including washpost.com whose goal is contrary to FR, a claim may be made.
At which point FR notifies it's user base who become aware of the issue and refuse to knowingly infringe. Clearly (despite my own personal wishes of the issue even existing) this responsibility resides with FR, which they do a great job of, God Bless their souls.
Point is, the problem corrected itself, even when two entities at opposite ends of the political perspective are involved. Could copyright claims increase to the point where FR incurs further claim damages? Possibly, but IMO that ratio is directly related to the quantity of infringement being perpetrated on the internet at large. Theft of music files increases that ratio.