What I find missing from a lot of the conversations on HN is why the power was used, and an overfocus on tech.
The people who marched on the capitol did it because their reality tells them that their country is being stolen, by Democrats. People will actively oppose the current administration, because they believe this is illegitimate.
Trump and the info bubble he inflates, collectively believe that American elections were a farce. Trump holds a 40% approval rating, down from 42% on Jan 1st. His party, and media enablers repeated and enforce this idea. If the coup didn't happen, they would continue to argue the point.
Parler? For all its claims to free speech, it enforced ideological conformity, as do a lot of conservative boards. Their reasoning is that you get banned for being a conservative. However they don't mention that they get banned for saying "COVID is a hoax", "Trump won" and the perennial "some communities just have problems". Death threats, hate speech are all too common.
That is how far things had gotten, before tech firms acted. If anything, they acted late, after the costs of inaction are obvious, and Trump is leaving the stage.
If you are uncomfortable with their power, know that research from 2016 shows that conspiracy content gets stronger the longer it is available and gets repeated. A fact absolutely not lost to tech firms.
Tech firms kept material they knew was dangerous, up longer, because they did not know how to handle the repercussions of doing the scientific thing when people think its the wrong action.