> My writing is my work, and Anthropic’s current strategy is aggressively writer-hostile.

If your writing is indeed your work then watermarking should not affect you.

Rands argument is that the following actions will also water mark their hand written text.

Synthesis Proofreading Translation Summarization Critique

It may just be a misreading but say you asked for a review of the text and it silently water marked it as its own. Guess source control to review changes is the solution.