The most likely reason he quit fighting (and you know this)is that he knows he is guilty and would be shown even more so that he is guilty. You know that that is the most likely scenario.
Again, your mind reading skills are lacking.
The fight against USADA takes time and (lots of) money.
USADA does not have the authority to strip him of the titles - per the governing body for the Tour de France.
USADA has already vowed to violate their own rules to pursue him on these allegations. And they will do so based on hearsay with no physical evidence.
He is retired - which means a lifetime ban is pretty meaningless.
So, he could spend a ton of money and a lot of time fighting charges that will have little effect on him, or he can simply state that he is done with it and preserve his time and assets.
Now, given this interpretation of the events, you appear to still prefer to assume that his leaving the arena is an admission of guilt.
You are correct in one respect - this is no court of law, although USADA has attempted to take on the mantle of authority under the legal rules it created for itself, despite flouting those rules. If this were a court, the judge would be impeached.
If you would like to continue a logic-based discussion, I would be willing. But the emotional appeals you are resorting to have no interest for me. I am not persuadable based on one-sided assumptions, no matter whether you believe them to be appropriate or not (they aren’t).