How did people forget about the D'denir being Kalad's phantoms?

[Arcoss]

I just finished Warbreaker and can't find an explanation for this

How can Peacegiver send all of these lifeless into the largest city in the region and then somehow purge all information about their true nature?

Even if they were carted in as statues people should have noticed they look exactly like Kalad's soldiers

 

[Weltall]

This would be the same population that forgot that Strifelover and Peacegiver were the same person in less than three hundred years. The priesthood probably encouraged this since a heroic Returned saving the kingdom makes for a better origin story for the God Kings than 'our leader started the Maywar, then thought better of it and set about ending it, whoops'.

As for Kalad's Phantoms, the average inhabitant of the city isn't likely to have ever seen these new Lifeless and would accept at face value that what looks like very well-made statues are just that. Especially since they were a new concept (and one not rediscovered since) so there was no basis for the average person to even think that a statue could be a Lifeless.

[Tsidqiyah]

This is a phenomenon that occurs regularly in our world. The knowledge of the ancient Greeks, Egyptians, and Persians was lost to later generations and historians are still lost as to why and how. But in as little as two generations whole swaths of knowledge can be lost.

Edited September 7, 2017 by Tsidqiyah

[Yata]

Probably the people didn't forgot it.

Simply they never know the Kalad's Phantom were stone beings, it was almost a secret weapon you know there is but you know what it is.
Then after the War, Peacekeeper simply made the statues be taken into the city and nobody could suspect anything (I don't think the statues arrived on their own feet where they will stay for centuries.