Well, the founding fathers intended for the First Amendment to apply only to acts of Congress, and maybe not even then (for example, just six years after ratifying the Bill of Rights, founding father and second President John Adams signed the Sedition act [0], which criminalized false and malicious statements against the government).
It took over 125 years before Supreme Courts started reinterpreting the First Amendment to apply to some government actions that weren't acts of Congress, but there are still tons of situations where regular people can restrict free speech. For example, in Frederick v. Morse, while the Olympic torch was running through some town in Alaska, a public high school student unfurled a banner that read "bong hits 4 Jesus". Despite this not being on school grounds and the student not going to school that day, the school suspended him explicitly because of the speech on his banner, but the SC said that's fine.
(Sidenote: I wouldn't look to the SC for coherent reasoning; the SC has been an absolute dumpster fire for all but the Warren court and parts of FDR's court. Hell, three current Justices (Roberts, Kavanaugh, and Coney-Barrett) worked on George W Bush's legal team in the democracy-negating Bush v. Gore case)
It took over 125 years before Supreme Courts started reinterpreting the First Amendment to apply to some government actions that weren't acts of Congress, but there are still tons of situations where regular people can restrict free speech. For example, in Frederick v. Morse, while the Olympic torch was running through some town in Alaska, a public high school student unfurled a banner that read "bong hits 4 Jesus". Despite this not being on school grounds and the student not going to school that day, the school suspended him explicitly because of the speech on his banner, but the SC said that's fine.
(Sidenote: I wouldn't look to the SC for coherent reasoning; the SC has been an absolute dumpster fire for all but the Warren court and parts of FDR's court. Hell, three current Justices (Roberts, Kavanaugh, and Coney-Barrett) worked on George W Bush's legal team in the democracy-negating Bush v. Gore case)
[0] https://en.m.wikipedia.org/wiki/Alien_and_Sedition_Acts