Imagine a hypothetical, well-intentioned free speech focused platform, without censorship and with low moderation: it will attract those people because those people have nowhere else to go. That strategy is a non-starter. The real requirement is that we are pushing for a world of auto-moderation where robots have to approve every single thing we say online - otherwise you are not allowed to let people communicate.
You platform is indeed hypothetical because what you're asking for is essentially impossible. Low moderation just doesn't work at large scale without a substantial number of people suffering from its effects, including harrassment, threats of violence, spamming, and child pornography.
I would say that this hasn't been possible for at least the last 15 years.
Just to be clear about this specific case: There is "evidence" (Twitter posts) coming out that showed that all new users of Parler were shadowbanned by default, until their posts/content were approved by a small group of "right-think" moderators.
So while your hypothetical isn't invalid in general, it's really not what was happening here with Parler.
What they said they were trying to be was not at all what they were actually doing - a common theme in extremist spaces.
But your overall concern about the concentration and centralization of our communications is legit. There's no easy answer there.
Right, if someone wants to build a business and can't do it without making it easier for hate groups and terrorists to organise, why would any government allow the business to exist? It's fundamentally a threat to any nation for it to allow profit from enabling sedition.
