Actual calls to violence are a clear line in free speech. Telling someone to blow up markets and commit terrorism is something everyone should be opposed to.
There was a lot of speech other than direct and immediate calls to violence that were/are censored.
Regardless, if you read the GP's post, they're saying 'words' should never be banned. So I don't see the making an exception for even the kind of violent speech that you stated. Where were these free speech absolutists back then when their personal misinformation and racist speech wasn't being affected, but others' was?
Most free speech proponents agree that calling for violence is wrong. To ask extent encouraging others to break the law is wrong (to an extent, because I've way to get rid of an unjust last is to break it)
Regardless, if you read the GP's post, they're saying 'words' should never be banned. So I don't see the making an exception for even the kind of violent speech that you stated. Where were these free speech absolutists back then when their personal misinformation and racist speech wasn't being affected, but others' was?
Makes me doubt their principles.