My position is that "complete abandonment" and "she no longer believes in the theory" are your quotes, and not Shelby's and not even Rachel's. Regardless of what you understood Rachel said Shelby no longer believes, the fact remains undisputed that we have seen no answers about the source, just unproven theories. The CAS proceeding did not provide us these answers, no prove any theories.
Saying I don't understand legal proceedings is not only wrong, but a copout. I'm sure the CAS understands legal proceedings, and they explained their thought process and justifications within the applicable standards quite clearly. Their primary findings were that Shelby failed to rebut presumptions on the balance of probabilities. As a consequence, it is the WADA Code that compels the CAS to deem intent and sanction Houlihan for 4-years, as if she were truly an intentional doper.
Note that judges in real courts have also been known to wrongly convict innocent people, and even sentence them to death, due to judgements made on incomplete evidence, and sometimes with the help of dishonest prosecutions withholding evidence. The real truth behind events cannot come from an abbreviated process that doesn't look for the truth.
With your DUI analogy, I'm not sure you can win a case by proving someone else gave you alcohol and threw you in a car. Laws may vary from state to state, but according to Neil Shouse, former Los Angeles prosecutor, intent is not an element to consider:
"Driving under the influence (DUI) is a good example of a strict liability crime. People commit DUI when they have a blood alcohol content (BAC) at or above the legal limit, usually 0.08%. They do not have to do this intentionally or even negligently because a culpable mental state is not an element of the crime. All that prosecutors have to show is the BAC level."
The DUI analogy fails because it is not sufficient to just show the level. According to WADA, "low" levels of 5+ ng/ml and CIRs of -23‰ can be "endogenous", and therefore would not be an AAF and not an ADRV.