the fact that john was fucking LYING when he told augustine in HtN that his pre-resurrection self would have hated him for saying no one needed to be punished for what happened to humanity anymore. from john's own mouth, augustine back then was apparently working towards a solution of getting as many people from earth to safety as possible and then turning towards what they could do to help the planet heal once that was done -- prioritize helping people survive first, solve the underlying problem after that and tentatively they could maybe one day return, pretty logical and straightforward. he didn't care about stopping the trillionaires because he wanted to punish them for abandoning earth, but to force them to take on more people in cryo before they left, save more lives. he seems to have thought that was what john wanted too, because apparently his and mercy's enduring mistake is to think (hope?) that john is a better man than he is -- or even to think that he's not a monster. (big 'when is a monster not a monster? oh, when you love it, of course' vibes.) and john wiped his memory of everything that happened and lied to him about who he'd been for ten thousand years because in his heart of hearts john can't imagine anyone not agreeing with him deep down, not feeling what he feels -- I think he thinks that's what love is, someone subsuming themselves completely into his desires and needs without question. surely, if I show them all the state of the world without letting them have their preconceived ideas, they'll agree with me completely about what needs to be done, because they love me.
(john wants everything to love him. god must be able to touch all of creation.)
and when augustine inconveniently still turns out to be his own independent person with different views and priorities, even when john tried to control everything he got to know about himself, by the time the jig is well and truly up... he keeps lying to try to stop it from happening, to no avail. when they believe john is dead, augustine's plans and values seem pretty much consistent with those of his pre-resurrection self, if severely warped and dented from ten thousand years of, y'know, all that being effectively the second in command of a fascist death empire stuff. he still wants to save as many people as they can and doesn't give a fuck about getting retribution out of it. find our survivors, sue for peace, find them a new home, let necromancy die. his wildest dreams for what to do after have downgraded from 'and then maybe save the planet!' to 'and then mercy and I can hurl ourselves into a sun, probably squabbling the whole way, and get to be done and forgotten together', which is understandable under the circumstances lol, but to me this is still pretty clearly recognizably the same way of thinking, a consistent personality shining through -- not fundamentally in opposition to his old self at all. if his pre-resurrection self would have hated him for anything, it's probably for choking down his little brother's soul after not being able to save him, huh.
and the worst part is that john could only do this to them because they did love him. they loved him so much, and john wants their love so much he tries to eat them whole and make them parts of himself. he had what he wanted, and he corrupted it beyond all recognition until it was, to quote alecto, a hideousness, and now he's all alone. they held his hands when they died the first time, and he thought the way to deal with that was to try to make them his hands so they couldn't be taken from him again or leave him, couldn't be separated from him. “If I forget you, let my right hand be forgotten”.
it's time to stop kidding yourself, john. no one else is fooled anymore.