Parler wasn’t upended because of what was on the site or any laxity in keeping advocacy of violence off of it. Rather, it’s been a target of a big tech conspiracy because it’s a platform for conservatives. From Tyler O’Neil at pjmedia.com:
In the days after the Capitol riot on January 6, 2021, Big Tech moved against a conservative alternative social media platform, Parler, based on the premise that the rioters has used Parler to plan the attack on the Capitol and that Parler had failed in its responsibility to prevent such coordination. Based on this narrative, Apple and Google removed Parler from their app stores and Amazon removed Parler’s internet hosting. Yet on Thursday, Parler flipped the narrative on its head.
The letter details Parler’s efforts “to flag and remove unlawful speech from its platform that was not protected by the First Amendment.” It also notes that of the 270 charging documents filed by the Department of Justice, 80 percent of social media references involved Big Tech platforms like Facebook, Twitter, and Instagram. “Only 5% referred to Parler.”