Social media generally does not talk about "free speech" because they know there is no such thing. Every human group enforces some taboos. If it is not banning child porn, it is social prohibitions on mentioning the embarrassing secrets of others.
This is separate from the political concept of free speech, which has been entirely abused. The original idea was simply this: government could not pre-emptively ban the publication of political, philosophical and religious opinions.
It had nothing to do with the "right" to scream obscenities at nuns, be naked in public, download bomb-making instructions or the like. It was designed as a way to stop the type of government censorship which had become rampant in Europe after commerce took over from the kings.
In online forums, it means something else: the ability to talk about anything, if it is put into the right form. That is, if you think that diversity does not work, you post logical arguments and statistics, not racial slurs. Unfortunately, very few of our caste-mixed and cultureless population can do this.
On the other hand, there is political censorship of the type free speech was designed to prevent. This is now conducted almost entirely by private companies because they own the means of publishing in the age of social media and blogs on Blogger (Google)/Wordpress.
Reddit claims that it supports free speech, yet everywhere, opinions that are in the right form are censored because of their content. Free speech on Reddit means free speech for Leftists, as it seems to mean everywhere Leftists gain control.