The lawsuit, filed in December 2016, accused Facebook, Twitter and YouTube (owned by Google) of knowing that ISIS recruited members online and doing nothing to stop it. Because the Pulse gunman, Omar Mateen, was able to view extremist propaganda on these social sites, the lawsuit said they were civilly liable. The complaint demanded a trial by jury.
"Without ... Twitter, Facebook, and Google (YouTube), the explosive growth of (Islamic State in Iraq and Syria) over the last few years into the most feared terrorist group in the world would not have been possible," the complaint reads.
CNN has reached out to Facebook, Twitter and Google. Twitter officials declined to comment. Google and Facebook have not responded to interview requests.
The attorney for the families, Keith Altman, said his clients will appeal.
"We are not surprised that the law is unsettled in the terms of holding social media companies accountable. We will absolutely appeal," Altman said. "We feel the judge didn't see the case in the right way and will continue to fight. We have just as much resolve as we did before."