Humanity isn't something we verify it is something we cultivate.
The obsession with verification comes from an empty conception about humanity.
The question isn't really how do we verify which of us is human, the question is what spaces have degraded sufficiently that the mark of human interaction is no longer discernible in the noise and what are the mechanisms in which they have done so?
Systematic tolerance or indifference to hatespeech is one great way to degrade the humanity of a space for example.