Punitive damages are about punishing a company so they actually feel some sort of pressure to change whatever behavior caused the incident. It’s not about the specific single incident.

The fact this is similar to the McDonald’s hot coffee incident from a couple decades ago means that Starbucks already had a clear indication similar operations could lead to this, and did not have proper solutions in place to prevent a known possibility from happening. Looks like pretty clear negligence, to maximize profits, which means massive punitive damage to offset those profits.