There is a huge difference between a platform censoring/banning you and a community on the platform censoring/banning you. No irony involved. That subreddit is just trying to have discussion among like minded people without trolls and brigaders disrupting everything, they are a highly targeted subreddit for those acts. Reddit as a platform still exists for you and joining or making new communities is possible at the click of a button. Contrast that with having to create your own platform which is prohibitive, or migrating to another platform (if one even exists), which is also prohibitive.
And now we have a most recent grievance of a group getting removed from all platforms, creating their own platform, only for it to be removed from existence by mobile devices and web infrastructure dropping it.
It's totally fine to create a closed group to talk amongst like-minded people, just don't try to make a claim that it's superior or pro-free-speech.
To the credit of the moderators of r/conservative, they don't really claim that, though some of their users try to. They're very open about their intentions. They absolutely do not welcome non-tribe members.
And now we have a most recent grievance of a group getting removed from all platforms, creating their own platform, only for it to be removed from existence by mobile devices and web infrastructure dropping it.