Your sentiment is the vein of the Turing Test, which seeks to unask "Are machines capable of intelligence?" and replace it with "Are machines capable of fooling human beings into thinking that they are human?"
Personally, I do not like it. I believe that thinking and acting rationally is different from thinking and acting like a human. I might put you in a room with a hypothetical automata that could perform many different tasks, answer your questions, and shows you how it survives, yet didn't think like a human. You might be freaked by this creature, but it would act alive and rational, yet inhuman.
I believe that it is inevitable that some or most humans will choose to undergo transhumanism, especially when confronted with difficult tasks, like space travel, where our meat bodies are at an incredible disadvantage. I also believe that some humans will shun this transformation utterly. I choose to consider humans that transform their bodies still human.