Why isn't the FBI raiding all Silicon Valley companies like Facebook, Twitter, Instagram, WhatsApp, TikTok, Reddit, Google, Yahoo, YouTube, Disqus, Wikipedia for censoring the World through their Ban cartel violating the constitution freespeech laws?

They have not violated the U.S. Constitution and freedom of speech laws. Dunno about other countries.

What arguments like this fail to recognize is 1A means you have the right to keep your damfool mouth shut. 1A means you cannot be forced to say anything, a right backed up by 5A. 1A and 5A as they apply to speech prevent government from forcing you to say something AND stop government from not letting you speak.

Government owned companies are also covered by this, but these companies must allow speech the company may not agree with.

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Should newspapers be forced to print every letter ...

Restrictions of course apply. See Supreme Court rulings on what can be restricted, i.e. child porn, inciting to violence and a couple of others.

Lemme make this simple - Freedom of the press belongs to the person who owns the press. You don’t like what a particular press (the social media you reference above is the press in this case) does, start your own and you make the rules.

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Companies that are privately owned, owned by stockholders, etc. are also covered by this. These companies cannot be forced to provide space or a platform for speech they do not agree with. This is freedom of speech. I realize you may disagree.