I did, and I still don't understand why it's a necessary abstraction. As I said, you shouldn't be thrust into a struggle session at work independent of when you entered the conversation or whether you entered into it at all. That's the whole point of liberal order-- equal justice under the law.

Nobody is trying to get responders to shut up. They're trying to stop responders from shutting up the initiators. The distinction between the two is that the latter is usually qualitatively escalatory.

Alice makes a joke on Twitter, but rather than respond on Twitter Bob calls her employer. Alice schedules a talk at a university, but rather than scheduling a rebuttal Bob calls the university demanding to cancel the talk. Alice writes an op-ed, Bob publishes her address.

Both are speech, but a cultural norm of escalation makes the culture a pretty awful place to live.

Ken's idea of "First Speaker Problem" is that you're giving Alice additional rights/consideration/privileges when you apply the abstraction of "initiator" and "responder", rather apply the "speaker" abstraction equally to everyone, and that that different is a Problem.

FSP isn't an abstraction, it's a named bug.

Everything else you're saying is just Ken's point about proportionate response.