I am just rereading Oathbringer for the first time and picked up on something I missed.
When Dalinar takes Navani and Jasnah to the Recreance vision Jasnah mentions something about the "False desolation" that the church said happened as all the Voidbringers hadn't quite been defeated. She speculates that this would have happened before Parshmen lost their songs (although obviously she doesn't put it like this).
I agree that simply finding out the truth of the invasion isn't enough but maybe finding that out couple with the enslavement of the Parshmen was enough.
I am sure this has been speculated on before but I am brand new to the community for Stormlight and have just read this part before I looked on this forum.
