Correct. And is the necessary escalation when online-only tools have failed and the attacker will not relent (such as this circumstance, where the actor in question is taking active steps to bypass methods to down-sample their signal).

I'm assuming most people holding a position in this conversation aren't absolutists (for example, they recognize why the FBI honeypots / tricks people / subpoenas information to de-anonymize those suspected of crime). Is the issue which hands hold the power / take the step of de-anonymizing someone? If that is the issue, what is the recommend course of action in this scenario (which exceeds people's tolerance to continue to operate freely in the OSS community without harassment but does not meet the threshold of an FBI criminal investigation)?

In fact, the opposite right (the right to face one's accuser) is enshrined Constitutionally in the United States when we bring the force of law to bear on a citizen.

Anonymity has value in specific contexts. It is not a universal right in all contexts.