A good book on the concept of free speech is "The Case Against Free Speech" by P. E. Moskowitz:

Journalist P.E. Moskowitz’s latest book The Case Against Free Speech is provocatively titled, but does a good job of persuading why we ought to regard free speech more like magical unicorn horns: as something that does not exist, has never existed, and fundamentally can never exist in the world we’ve created.

But the author goes further, and they demonstrate how those who fight in the name of “free speech” end up working on behalf of fascists, transphobes, misogynists, and petro-billionaires — to extend the analogy, actively aiding rhinoceros poachers on behalf of defending the principle that magical unicorn horns should exist...

Moskowitz’s book, by centering power in the evaluation of speech’s freedom, reframes how someone who supports the ideal of free speech ought to focus themselves.

The ACLU does not have unlimited resources. Every time it throws some of those resources toward Nazis, it comes at the expense of DAPL protestors arrested for standing on their own land, Black Lives Matter organizers personally sued for the actions of anyone in their march, or trans people fired for existing.

Nor do you, with your time, attention, or energy have unlimited resources. Whether it’s tone-policing college students who want to feel safe from physical danger on their own campuses or showing solidarity with white supremacists under the guise of free speech, it’s not a neutral act, regardless of whatever appeals to neutrality you want to make. Free speech does not exist, it never has existed, and it probably never can exist under the current system.

So if you’re going to go out of your way to advocate for something, the least you can do is come up with a reason for the thing you’re actually advocating for rather than hiding behind a fantasy to avoid acknowledging what you support.