Let's review what happened with Parler.
It started off as a small irrelevant site, as they all do.
Twitter and Facebook then started labeling content on their site with "fact check" labels. This is naturally fraught with scandal because doing this at scale involves a lot of mistake making and then you can find arbitrarily many examples of them authoritatively declaring something as false or "disputed" when it wasn't. There was a strong perception on the right that these tags were being attached to things on a partisan basis.
A number of people didn't like this and started looking to alternatives, so Parler started gaining users.
Then those jackasses stormed the capitol. Note that this was planned, openly, predominantly on Facebook.
The response is Something Must Be Done, so there is a mass banning of accounts, including the then-President of the United States. Doing this was even more controversial, there were questions about whether all of them deserved it, and a lot of people -- the vast majority them people who hadn't been banned -- started moving to Parler in protest. They hit ten million users.
This was now a moral panic because Parler is owned by right-leaning people instead of left-leaning people and the whole deplatforming system is based on the targets not having anywhere to go. So then regardless of who they really are, they now have to be demonized in order to justify their destruction, because they're getting too popular. Note that popularity and extremism are anti-correlated because extremists are by definition at the fringe, so the more people you have, the more diluted the extremists get. The logic was backwards if the real problem was what they claimed.
But people find a list of malicious posts on Parler to paint the entire site as that. These exist everywhere so of course they found them. Made all the easier by the fact that they were undergoing rapid growth and at that specific moment in time their moderation system was overwhelmed. Also, point to moderation features designed to promote stability and exclude extremism by limiting what new users can do and claim that they do the opposite under the unproven assumption that the site is already dominated by extremists and the same features would then be excluding non-extremists.
I'm sure 80% of Parler is crap, because 80% of everything is crap. But then how are we distinguishing it from Twitter? None of the evidence used to "prove" that they weren't moderating when they claimed to be couldn't be used to prove the same thing of their competitors. It's an isolated demand for rigor.