Basically, as far as I can see, it was around the time of the Carlie Hebdo shooting that free speech started being viewed as a right wing perspective. For most of Western history of which I'm aware, that wasn't the case.
Still, in the academy, left wing hostility to free speech was already creeping up.
Christopher Hitchens sadly passed away before "micro-aggressions" and "trigger warnings" became part modern vernacular. Years before Charlie Hebdo, Hitch gave one of the greatest defenses of free speech I've ever heard.
Hitch, for most of his life, was a man of the left - a Marxist. Another favorite orator and writer of mine on this issue is man of the left, Brendan O'Neill, who also considers himself somewhat of a Marxist. Bill Maher is certainly man of the left and he's been good on free speech; but, he has a glaring blind spot.
Salman Rushdie coined the term, "The but brigade." "I believe in free speech; but, you can't say anything homophobic." "I believe in free speech; but, you can't say anything that denies the Holocaust." "I believe in free speech; but, we need a bureau of fact checkers."
If you fall anywhere in there, no, you don't believe in free speech. If you won't defend the speech that you find wrong, uncomfortable, evil, so-on, you don't believe in it. I would appreciate it if everybody on that spectrum would just stop using the term "Free speech" to describe something that they support. It's a lie and it's making the problem look smaller than it is.
The best of my opponents on this issue believe in some sort of licenced speech. Most people, however, seem to believe in a system of, "Speak at your own risk and the mob will decide in the moment whether or not you have a right to live."
The most pervasive and popular "buts" still seem to be, "Get money out of speech." and "Corporations aren't people."
Bill Maher has been attacking the Citizens United ruling for years while missing the irony that HBO is a corporation funding his political speech and getting it out to the masses. The New York Times, the Washington Post, the Washington Examiner are corporations. Funny or Die is a corporation. Basically, if you want public speech, you need money.
Now, you might say that the solution is to only allow donations to political candidates. Well, you'd still be taking every major news program and most independent journalists out of the discussion. SNL wouldn't have been able to make fun of Trump or Palin while they were running. No independent filmmakers with an LLC would be able to produce politically motivated content.
Namely, if you're saying, "I believe in free speech; but, get money out of speech." you're in the but brigade.
It seems like a lot of people wouldn't even allow a person who they don't like to use a bullhorn, standing on a soapbox in a public park without threat of violence.
It's unpopular to admit that you don't believe in free speech. That's good. But, be honest and just admit that you're willing if not enthusiastic to destroy the foundational value of liberal society for your comfort.