This only proves that the Big Tech companies need to be regulated and that Section 230 should be repealed. Break their power! Parler should sue them for billions. The federal gov't should also sue them for antitrust violations.
Parler should sue AWS for billions when AWS asked Parler to build a process that reduced violent content and Parler refused?
Also, the US has free enterprise. Businesses are free to choose who or what they do or don't do business with. Parler can sue all they want, but its a waste of their time and money.
Parler may still be liable for the violent coup content; liability for that isn’t exclusively, or even mostly, the kind of “civil liability dependent on status as a publisher” that Section 230 provides immunity from.