Selective banning of voices that are "too far left" or "too far right" on Twitter, Facebook, etc wouldn't matter at all, except the citizenry has allowed these social platforms to grow so large they've become synonymous with culture and politics.
Ecosystems need biological diversity and the same is true of publishing.
An infrastructure of independent web hosting, self-publishing, even search still exists outside the Google/Facebook/Apple/Amazon borg.
Use it! That is all.