[_heimdall]

Isn't there a bit of selection bias or similar there?

What kind speech would need to be defended with such a moralistic statement?

It seems to me like phrases like this are the go-to when defending speech that many or most might be offended by. If most aren't offended by it there's really no defending needed.

[rendall]

It's about defending the principle of free speech rather than what someone said.

To your point, only reprehensible or unpopular speech must be defended by the principle. As you say, speech that is popular and uncontroversial would not need defending. Do you want to live in a society where you may only express approved and uncontroversial views? If you have controversial or unpopular views, then you protect your right to express them by defending the principle of free speech, even for those with whom you disagree, even abhor.

[_heimdall]

Oh don't get me wrong, I completely agree with you here. I believe strongly in what most would today call "free speech absolutionism", though in my opinion that phrase is absurd since you can't have free speech with some limitations.