I have seen people with their minds damaged or partially lost, but once it is truly gone, so is their soul. [And then they're very dead indeed. A creature like Sebastian should be able to tell with certainty, right? Yes, he's sure.]
Naturally, young master. I am commenting neither on their accuracy nor what right they delude themselves to have to make such judgements. [Calling the Reapers(?) deluded is no subjective comment, obviously. Sebastian's own list is very... Any demon's list of crimes would very much like this. He's not even sure if it's tailored to him or not.]
Does this entire message not seem designed to unnerve and confuse? [Including the "bodies and consciousnesses separated" part. If Ciel's crimes are accurate, it's not a long leap to assume they'd know it'd unsettle him to be told such lies.]