Dixon gets charged with setting an excessively slow pace & Cockburn gets charged with not giving his horse the best chance to win (basically).
The excessively slow pace rule was put in place to guarantee drivers following that they wouldn't have to bust their horses to try & force the pace.
I think Cockburn should have protested. He's well within his rights & this rule is yet to be tested under protest.( that I know of ).
Cockburn IMO did nothing wrong.