It's intrinsically linked to "free speech" exemptions through being violent, because violence doesn't have to be physical, here's an excerpt from Wikipedia's opening paragraph on violence[1]:
> Other definitions are also used, such as the World Health Organization's definition of violence as "the intentional use of physical force or power, threatened[4] or actual, against oneself, another person, or against a group or community, which either results in or has a high likelihood of resulting in injury, death, psychological harm, maldevelopment, or deprivation."[5]
There's no doubt that hate speech _does_ commit psychological harm, for example, but the article contains way more nuance than I have time for in this post so I implore you to read the article -- "violence" is just not as simple and limited as physical harm.
[1]: https://en.wikipedia.org/wiki/Violence