Well I suppose it’s an argument, Hawk, but where would you stop? There’s many a race lost because a jockey has made a mistake positioning their horse or timing their challenge, there’s many a jumper floored because their jockey made a mistake and misjudged the fence. And so on.
In this case it wasn’t the mistake that was penalised, but that it led to him not riding out the finish, which was the offence. If you tried to introduce a rule relating to “mistake” it would surely prove a nightmare and almost impossible to police.