During the civil rights era, private businesses infringed on people's rights with state government backing. People with the wrong skin color were forbidden from being in certain restaurants or sitting in certain seats, etc.
These were private companies infringing on rights.
Again, you are conflating rights granted by the constitution with legislation that dictates how businesses must operate. Racial discrimination in public accommodations, like those that you mentioned, was outlawed by the Civil Rights Act of 1964[1]. In that case, those private companies were explicitly breaking federal law. Rights granted in the constitution are separate and are only intended to protect citizens from the government.
The constitution does not grant rights It merely enumerates some of the rights we have.
The civil rights act did not make up any rights - it created law to enable enforcement and protection of rights people already had, but which were being infringed - both by states and by private businesses.
The social media monopolies are infringing on our rights. There may not as yet be a legal remedy for that, but it seems likely that there will be, as in many ways these companies are more powerful and wield more influence over people than governments do.
I think that you have a general misunderstanding on what a "right" is in the eyes of the law[1]. Furthermore, you appear to also have a misunderstanding of the differences between natural rights and legal rights[2].
> The social media monopolies are infringing on our rights
The right to free speech is not a natural right; nor does it apply to anything but freedom from government persecution on the basis of speech. Freedom of speech is a right that is granted by the constitution and has been further defined by case law over the past 250 years. The Supreme Court has pointed out that private companies are not subject to protections enumerated in the constitution, which, again, only apply to the government[3].
These were private companies infringing on rights.
The president sent in the national guard.