Indeed NO information is far better than unreliable information. Why ? Because with no information, you try another venue to get info, other traditional method maybe, and try to correlate bits of clue between each other. But with unreliable and probably false info, you concentrate your resource on what could fully turn out to be a dude, and thus lose time, money.
If people were using the unrelible info as just a low value bit to be correletaed by other method, it would be OK. But the problem is that the troture proponent are actually trying to use it as a shortcut to results.
It's not just that, it's that it produces actual damage. In this case it's even spelled that brain tissue is genuinely damaged. That is, in addition to genuine psychological damage.
Even if the guy turns out to have been innocent, even if you screen the information and it's false, you still caused actual harm to an innocent.
I don't see how any kind of screening or correlating the information, can excuse that basic fact. You can't treat it as just some information that came out of nowhere and look at just what you do with it. The hard fact is that that unreliable and false information, came at the expense of harming an innocent. That's a price that most of the civilized way decided it's not worth paying.
Then there's also the fact that it's an abusable thing. There's a reason why since the Magna Carta (and in several ancient civilizations before it), we want checks and fair rules, and why the focus is more on protecting the population from abuse than on delivering quick results for the cops. We all have tried just letting the king's guards kick and door in and torture anyone they want until he/she confesses, and it didn't work so well. Even for those who weren't at the very top, it wasn't an ideal situation: the Magna Carta was forced upon the king by the barons, not by the peasants.
There's a reason why we have rules like innocent until proven guilty, habeas corpus, etc. Or why the phrase "
nor shall be compelled in any criminal case to be a witness against himself" exists in the 5'th ammendment. Torture proponents don't just do this and that with information, but genuinely throw those safeguards and checks away.
And it's no surprise that even in modern times the power of any oppressive or totalitarian regime was based, basically, on throwing those safeguards away. And on then using the threat of unjust punishments or torture as a threat to keep the population in line.
So now turning it all into just a discussion about abstract correlation of data is missing that crucial point.
Plus, how do you enforce correlation. Once torture is allowed, and given that it makes someone confess anything you want to hear, it's trivial to use it as correlation for some other false piece of data.
E.g., it's trivial to get several innocent people to confess the same thing, and then take it as correlation. The witch trials not only produced thousands of people who confessed the same crimes and in the same details, but an amazing confirmation of everything in the Maleus Maleficarum. Because everyone was asked the same thing.
E.g., it's trivial to get someone to confirm any other piece of data you have, no matter how false and unbelievable. If you get a prank tip that terrorist group Onan's Witnesses is planning to storm the white house and give the president a bukkake, you can torture some people until they confess not only the group is real and they're members, but even agree on exactly what date the attack was planned for. Gee, what an amazing correlation.