This doesn't prove that a human "can't think". It proves that a human can't provide a logically consistent answer to a question that doesn't have a logically consistent answer.
This isn't quite analogous to the situation in the parent. There exists a logically consistent answer to the question "tell me something other than what [algorithm] would yield from [inputs]" -- it just can't be produced by that algorithm.
It's exactly analogous. There is a logically consistent answer to the question "tell me something other than what Joe McBlow would do in situation X"; it's just that Joe McBlow can't give it to you.
This isn't quite analogous to the situation in the parent. There exists a logically consistent answer to the question "tell me something other than what [algorithm] would yield from [inputs]" -- it just can't be produced by that algorithm.