Well, that doesn't mean that
a) they were right to do so then, or
b) a better understanding can't have been reached since then.
The Paradox of Tolerance is a very real thing. If you want to make free speech absolutism a religious principle within your own beliefs, go wild, but for those of us who just want to make this world the best place we can to live in, we have to consider what the consequences of different kinds of speech are.
And the consequence of being tolerant of hate speech is that the speech of those being hated diminishes. Their freedom diminishes. Their safety diminishes. Sooner or later, they are driven out of communities that permit hate speech against them.
"Free speech for all", in the sense that absolutely anyone is fully free at any time to say anything they want, and everybody remains equal in this, is a fantasy. And American jurisprudence has rejected that level of "free speech" since very early on—there are laws against libel, incitement to violence, false advertising, and other forms of speech.
This phrase needs to be used (and understood) more often. People who act in bad faith use this to their advantage and make our society worse. Look at the response to the Kirk murder: people were fired for daring to say something negative after his death.
So the only way to keep society safe is super smart people like me get to control what other people can say - reasoned as always in such a sophisticated way.
As always, society carries on only so long as its enemies are kept at bay.