This issue is mentioned on the Opus 5.5 post [1] from Anthropic (no idea if it has been added after your rant):

  > Don’t ask it to show its reasoning in the reply
  >
  > What to do. Remove requests to reproduce its internal reasoning in the reply from your prompts and instructions.
  >
  > Why it matters on Opus 5.5. A request to reproduce its internal reasoning in the reply can be declined. It’s one of the flag categories.
  >
  > How. Ask Claude for what you need instead, for example, “Explain why you chose this approach in three sentences.”

Anthropic is trying so hard to "crack down" on distillation that they're ruining their own product. I do not know why.