Well it’s pretty simple, by going in to the passing lane earlier than was permitted, he gained a momentum advantage that allowed him to get up and win by a nose. If he waited for the passing lane to open up, he would have been a stride or two slower getting going and not won the race. He did, in fact, gain a winning advantage by breaching the the rules.
rule states
(7B) Where any horse or its sulky wheel moves inside the track marker line and gains an advantage the horse shall be disqualified from that race except where it is established that the breach was caused by interference by another horse or driver.
the Stewards and JCA were only applying the rules correctly to protect the interests of punters on Vintage Rose.