The first amendment applies to individuals not publicly traded half public-half private entities.

Facebook is the government. The white house under the current regie and state of California both admit that they have backdoors into Facebooks bureaucracy they use to ban content. Facebook is already merged with the Chinese state apparatus in china.

As such they ought to be regulated as a government agency. Those do not enjoy first amendment rights. Ones first amendment rights end the moment they accept being part of the government.