“No harm no foul” is a pretty good guide. Even in law, if something is done wrongly at trial, if it is found that the wrongdoing did not affect the outcome of the case, the wrongdoing is considered of no effect and the case is closed.
Here, although MS did go into the other horse’s lane, there was essentially no effect. Both continued at their pace.
THAT should have been the major consideration, but apparently wasn’t.
I wouldn't go so far as to say the other horses "continued at their pace".... They did have to break stride, and re-adjust. But, that happens nearly continuously in a race like the Derby, with 20 horses.
All affected horses had PLENTY of time to recover, and take matters into their own hands. You're correct: "No Harm, No Foul" has been the standard in this race for a VERY LONG time.. and, it should have applied yesterday.