True, it is making an argument, but a much weaker one than those arguing for consciousness: it's demanding the extraordinary evidence Anthropic's extraordinary claim is making. It's applying Occam's Razor, which
does make a claim, but a much weaker one.
And to reiterate this, to me the most insightful part of the essay is that Anthropic either doesn't believe these claims, or they are monsters (much more likely, the former).