As many folks here now recognize, the story about Backpage was grossly misleading. While the narrative pushed by politicians and the media was that the company was engaged in sex trafficking, the DOJ had actually commended the company for being a strong partner in the fight against sex trafficking. Indeed, the eventual takedown of Backpage days before FOSTA went into effect (which we were told was necessary to shut down Backpage) has been shown to make life more difficult for law enforcement trying to stop sex trafficking.
But I thought politicians told us the truth? /s
tl;Dr The court made a weird ruling that says there is no secondary liability (Backpage) but there is tertiary liability (providers they purchase or contract with).