I think they're answering a question about whether there is a distinction. To answer that question, it's valid to talk about a conceptual distinction that can be made even if you don't necessarily believe in that distinction yourself.

As the article said, Anthropic is "working to identify and implement low-cost interventions to mitigate risks to model welfare, in case such welfare is possible". That's the premise of this discussion: that model welfare MIGHT BE a concern. The person you replied to is just sticking with the premise.