It's not speech but coercion that forces people to lose their jobs. Threats of boycotts and premanent brand destruction involve speech but it's an overly broad definition if you classify political action as speech.
The Constitutional protections in the first amendment of free speech, press, assembly, and petition are all largely motivated by the desire to protect political action, because restrictions on any of those things inhibit political action.
Its an overly restrictive definition of speech that excludes political action.
I think there's enough of a difference between mob-mentality and artistic expression that we can deal with them separately.
You can talk about different kinds of speech separately, but if you are talking about the entrenched American value of free speech, you ought not to separate from "speech" the kind of speech -- that directed at motivating political action -- that that value is first and foremost concerned with.