Not every platform needs to have _all_ the users. I know that it's a bit of an anathema on a discussion board built by venture capitalists to say that the goal of a social platform should not be to maximize the amount of users and engagement, but here we are. I think optimizing your service for "everyone" is a bad strategy in competing with existing social networks, especially coming from an "indie" background. Not that Parler is exactly indie.
[1] I'm saying this as someone that is working towards a discussion platform that targets smallish to medium communities formed around a common interest. In this world if moms wanting to share their latest knitting project are excluded from a service that targets free speech people, that's fine, there can be a knitting community out there also for them. Having these two communities intermingle by using something like ActivityPub is a way to keep "the network effect" but keep them separate enough.