Businesses can be sued civilly and (though rarely) prosecuted for criminally violating civil rights.
Corporations Have Paid Out at Least $2.7 Billion in Civil-Rights and Labor Lawsuits Since 2000
Big Tech can be sued for systematically firing those who have religious and conservative political beliefs in their workplace AND systematically oppressing them on the platform.
Well, of course they can be sued. The issue is freedom of speech and that applies only to governments. It has been long established that private companies can censure and permit limited speech. It happens every day.