No; the First Amendment prevents the government from limiting Sam's speech. Private companies can decide what speech is acceptable on their social media site.
Explanation:
The US Supreme Court already has decided that there are several categories of speech and that some of them can be limited by the government such as the ones that include obscenity, speech integral to illegal conduct, speech that incites imminent lawless action, speech that violated intellectual property law, speech that are true threats and others.
