I think this fundamentally misdiagnoses the root of the issue, post 2016-election. People have plenty control over what content they see (via follows, blocks, hides, downvotes etc), and existing social media companies are exceptionally good at figuring out how to show them more of the content they want. The problem is when it shows users content that they want but others don't want them to see, and in our current political environment there is no consensus on where the line is between being a responsible steward and censorship.
Put it a different way, if Truth Social had taken off users would have had "more choice" of social networks. Would the Mozilla leadership have considered that a good outcome?