Besides "attack" being a ludicrous name for distillation, note how your article says "accuses", also it's mostly about Alibaba, not DeepSeek (although it's mentioned there). Both Dario Amodei and Sam Altman publicly claimed that DS used their outputs to train their models, and knowing the differences between all these models by heart, I believe they're simply lying through their teeth to sway the public opinion and/or the policy. These models are absolutely nothing alike, and distillation necessarily makes student's outputs similar to teacher's. This is very visible in Z.ai models (which were trained on Gemini outputs to the point that they repeated Google's conditional prompt injections in the CoT, and later on Claude where it started repeating their CoT as well) and certain Google models which were trained on Claude's outputs in a roundabout way. Distillation always shows up in the result.

And certainly they have no idea whether these outputs (assuming they ever existed and it wasn't made up) were used for training. The article mentions that DS made 150k requests. This isn't much and might have been just an eval or a benchmark to compare their own model against. It's really hard to believe DeepSeek had any Claude outputs anywhere in their training schedule, since it's just too different. Besides training on random vibecode of course, which is mostly written by Claude.