Don't disagree with that statement. Rubbish in, rubbish out was one of the first rules of computers. Always has been and always will be.
The main problem with MEL was that SOP's were not followed. If they had been, the 100 tonne discrepancy would have been noticed. And for your information 411A, at no time did the Captain ever refer to Fatigue as a contributory factor. He did, however, refer to numerous distractions and interuptions from ground personel.
Cali was a different case altogether and while wrong info was inputed, the Captains confusion with the workings of the FMC was a causal factor in the CFIT. Along with many, many other factors including speedbrake design issues. But, let's not go there. Boeing certainly don't want to!
Harry