Parler is a Twitter competitor that's attracting conservatives, including politicians, who think Twitter is biased against them.
Parler seems to be banning a bunch of people. And it has the right to do so. Which is great. But what's not great is the site continues to pretend that it's some "free speech alternative" to Twitter when it's facing the same exact content moderation issues. And, yes, some people are claiming that Parler's quick trigger finger is mostly about shutting down "left" leaning accounts, but as with Twitter's content moderation, I won't say that for sure unless I see some actual evidence to support it.
It is impossible for a private company to guarantee you free speech, because they are vulnerable to legal, political, social, technical and financial pressures that fundamentally compromise that aim, however sincere or well-intentioned it is. And that (Zap! Pow! Dams burst! Bombs go off! Fireworks blast!) is just the way it is, folks.