You seem to be misunderstanding the question of consciousness. It's not about how you observe others to appear conscious, but about how you yourself observe your own consciousness.

> It's a lie our brain tells us [...]

Who is "us"? Or, to be more precise, if your brain tells you that you're experiencing pain, than what is "you", and what is "experiencing"? That's the question of consciousness.

This is not something we know how to observe and judge in others, you can only observe it in yourself (and draw conclusions about other people by analogy, i.e., due to similarity between our physical brain structures). For example, is the following Python script

    print("I am conscious.")

any more conscious than this one?

    print("I am not conscious.")

You'll probably say that they're both not conscious, although there is no hard evidence either way. And that's because we don't know how to reliably observe consciousness.