Which happens to have been exactly correct. Answer the charge, don't just snark at the source. Ad hominem attacks add nothing to the discussion.
Were the commissioners correct or not, when they said that Lincoln had toyed with them and misled them? Given the facts under discussion, it's hard to fault their reasoning. Or do you have a discovery that will change reasonable people's minds?
The commissioners were incorrect. Lincoln didn’t treat with them, didn’t think they had anything useful to say, and didn’t accept them as representatives of any legal body.
That message should have been very clear to them, the opposite of perfidity.
By contrast, they falsely represented themselves as represenatives of a sovereign nation, which they were not.
Their complaint is their perfidity was not accepted.
Call the Waaahmbulance.