I think the line is that when something is said which deliberately harms, offends, or causes aggressive physical situations, then it is beyond the realms of free speech.
I think the biggest issue has been the measure of what THAT all is. And to that degree, there has been an ultimately dangerous 'over-correction' which has now seen a pendulum swing back. Humour has suffered hugely, and a lot of what I would call average folk ended up being sucked into 'defending' themselves simply because they didn't 'proclaim' an issue. Social media has manipulated us into a society wildly divided, with architects on all sides 'benefitting' from sewing such seeds. I think it is tragic and dangerous, again on all sides. People are unfairly written off as 'fascists' just like people are unfairly written off as 'lefties' and both just become reactions to each other.
My biggest concern is that the whole idea and philosophy of responsible free speech is at a tipping point simply because no middle ground, or dialectic discussion, exists.