It's not. Like Todd, I've never been to a serious pistol class where accuracy was marginalized.
The problem is you're thinking of accuracy as an absolute, when it's really more of an abstract. Someone who's primary concern is defensive pistol shooting doesn't need to be able to shoot 2 inch groups at 25 yards. Would that be a cool and beneficial skill to have? Certainly. But it's not necessary to be adapt at using a pistol to defend your life.
Most instructors are bright enough to teach that there is a balance point between speed and accuracy.