When the criticism is wrong, or is not really criticism

When the criticism is wrong, or is not really criticism
Not everything hostile deserves an answer, and not everything that deserves an answer deserves a long one.
Sort it first:
— Wrong but sincere: answer once, with the specific reason, no condescension. Then stop. Others are reading, and you are writing for them.
— Right about something adjacent: acknowledge the valid part explicitly, then address the rest. This defuses more threads than any other move.
— Testing you: brief, unbothered, factual. Escalation is the reward they came for.
— Purely abusive: remove it under your published rule, without commentary.
— Endlessly relitigating: one reply, then "we will have to disagree", then genuinely stop. The second reply is optional. The third is a mistake.
The rule that has saved me most: never reply while irritated. Write it, do not send it, come back in twenty minutes. What you send will be shorter and better.
You are always writing for the readers, not the opponent.