1)By using the duck analogy; the speaker is basically saying 'It looks like a prison, and functions like a prison ,despite them calling it a clinic, so therefore it is a prison'. The title given to it does not change the intrinsic quality of it being a prison'
2) Deductive reasoning. If I hear a baby crying, I think a baby is making that sound. However it can be used to qualify a weak argument, where you do not have all the facts to hand and want to justify your conclusions to another. You are jumping from one piece of evidence (hoofbeats) and leaping to a conclusion (zebras) without all the facts available.(You have not seen that it is in fact zebras). In this case it is also being used as an analogy I believe.