A world where Twitter is controlled by a self-interested Musk, while Facebook is basically aligned with the US political establishment, enables better dissemination of ideas than a world where Twitter and Facebook are both aligned with the establishment. Because Musk has notably different biases than the establishment, and either platform is sufficient for the purpose of giving nationally-relevant ideas adequate distribution.
(For this reason, in a world where Musk already controlled Twitter, I would oppose anything that increased his leverage w.r.t. Facebook, because yes, you're correct that Musk's biases are not harmless.)
(For this reason, in a world where Musk already controlled Twitter, I would oppose anything that increased his leverage w.r.t. Facebook, because yes, you're correct that Musk's biases are not harmless.)