The confusion (ours, not yours specifically) might arise because some talk about free speech the principle and others talk about free speech the legal norm. (The latter is prominently codified in the US constitution and the Universal Declaration of Human Rights).

It's not the same and the principle isn't exclusively about government.

Free speech is also a very old ideal and exists in places where the US constitution doesn't apply and places where human rights aren't implemented through local policies. It can be violated in places where there is no government at all.

There's this great Wikipedia article on the topic which introduces first the idea, then different implementations: https://en.wikipedia.org/wiki/Freedom_of_speech