No one is moving the goalposts, I think it's rather the opposite. Every ten years computers learn a new trick or two and people rush to claim that this time, it's intelligent.
BTW I hadn't heard your Hamlet counter before, and I like it. A similar one might be: just because someone sold you the Brooklyn Bridge doesn't mean you own it. The flaw is there are other ways of checking those; for intelligence, there are none. Behaviour is it (at least, so far... still awaiting a non-behavioural definition of intelligence).
Besides, the original claim was that the goalposts are moving. And even if you hate the Turing test, it's clear that the goalposts are not moving.
I think the idea is that a machine that can emulate a human is necessarily intelligent because it can emulate intelligence. It's supposed to be similar to the way that you can know that a machine is Turing-equivalent because it can emulate a machine which is Turing-equivalent