How many times have you seen a whip used for control in a race? The whips major purpose is to encourage the horse to go/not stop. Maybe in a prelim with a young horse, on rare occasions, where a horse gets tapped to move forward etc a whip is useful. The $$ at the end of the whip is the real reason the drivers prefer to use the whip in my opinion but used the control issue as leverage.

But at the end of the day, as you mentioned, it gets back to the social license issue and you have to wonder how long the community can accept animals being beaten for entertainment/financial gain.