To be fair, he was originally willing to plead but the negotiations broke down; presumably, because the government was under the impression he was part of the Shadow Brokers, so they wanted to make an example of him and crucify the holy hell out of him. It, genuinely, sounds like the DA pulled their head out of their ass, finally, and struck a deal.
This isn't to counter your argument, whatsoever, but to reinforce it: If they were looking to give him 25 to life, that's something he'd, obviously, want to fight because it's disproportionate to the crime and it would be extremely arduous to keep going back and forth, trying to proclaim your lack of malicious intent, when the government has already made-up it's mind in that regard.
This isn't to counter your argument, whatsoever, but to reinforce it: If they were looking to give him 25 to life, that's something he'd, obviously, want to fight because it's disproportionate to the crime and it would be extremely arduous to keep going back and forth, trying to proclaim your lack of malicious intent, when the government has already made-up it's mind in that regard.