Spoiler Alert, click show to read:
Unsubstantiated accusations would not be protected by the First Amendment if they were tantamount to defamation. That is not the case here (most obviously because the claim made by Legio_Italica is true).Freedom of speech and unsubstantiated accusations are two different things. Your congress doesn't give you that right. If I say that US is more authoritarian than North Korea, and then I give references to the laws of the Russian Parliament, then I will look stupid in your eyes.
Trump's social media accounts should be restored, but the First Amendment only protects speech from state censorship.And stop talking about freedom of speech here. Return the account to Trump to begin with.