So basically both sides are saying the same thing, and are horrified at the thought that they would do such a thing.
Except...what we are accusing Chénier of is lying. Because we know that the things he is saying are untrue. Because we were there.
What he is accusing us of is knowing things that
we did not know and doing things that
we did not do. Things that he assumes to be the case from information he does have, and the way he believes Riombara to think and act. OOC, I am perfectly willing to admit that Riombara is far from the white knight realm it likes to think of itself as (especially under Delvin's rule!), but to suggest that (for instance) its leadership not only knew about the plans to secede half the realm to form a realm to ally with the monsters and either did nothing or actively abetted them, but also then spent the next 5 RL years lying about it, IC and OOC, is simply preposterous.