I’ve noticed a lot of confusion around what constitutes a violation of the First Amendment and free speech. The first and most important part of whether limiting speech violates the First Amendment is dependent on if it is the government stopping speech. If an elected official chooses to allow comments on their social media, they can’t just block certain people from commenting since they created a public forum through the initial action. They are not required to communicate this way, and are even free not to provide a response to comments, but preventing selected individuals from commenting is a violation.
Look at what happened in the ACLU of Rhode Island’s federal case Duhamel & Dubois v. Baldelli-Hunt for context. That doesn’t automatically mean everything said on these sites, however, is protected. The social media sites themselves could limit different kinds of speech since they are not government actors. Too often, people on social media will claim it violates their rights when a site limits their commenting, but it’s not a constitutional violation. The Constitution in these instances limits the government, not private entities. For example, a newspaper would be completely within its rights not to publish a letter to the editor it doesn’t feel comfortable with the content of. Ironically, many who cry about their free speech being violated will sometimes run groups on sites like Facebook where they create their own rules and limit others’ speech arbitrarily. The result may not be desired, yet it’s still legally permitted. The limitation on speech is only a constitutional violation if it is the government, or someone acting as a government representative, restricting speech.