That applies anyway, torture or no torture, Intelligence and professional interrogation is not made useless because someone discovers lying.
Interrogation is not based on the premise that a secret agent or a source of information is not allowed to lie, or that you have no idea what to ask them, or how to discern lies from truth.
They don't just grab a guy and tell him "you look interesting, tell us something, anything, about anything, we don't know or care, we just want to hear stuff, then we will dispatch a SEAL team behind enemy lines, or a high risk bombing raid, or call off a presidential trip for no particular reason, just your say-so".
All excellent points, though once again, the ultimate guide is Divine Law.