He admitted his guilt based on what the government stated it had for evidence, which is that the investigators allegedly had concluded that he lied in his interview. That was false. The 302's said the opposite. Further the government directly told him that he did not need to have a lawyer present in some of the interview because they just wanted some background information when in fact he was already a target. Not pretty.
In regard to the exculpatory evidence, the government has already been forced to turn over much by the judge so that point is beyond dispute, or at least to the judge who matters, not you. And his attorney alleges that there is more and wants to do more and has cited specific material that is being with-held. Your binary mind has determined that there is none but you don't know and you are not the judge. Much to your chagrin, some of these judges are not as happy and trusting of the FBI as you are these days and that works to Flynn's favor. The judge knows there was misconduct by the government. We are just talking about how much.
