Based only research and not firsthand experience, I think historically that is true. But over the last decade, particularly the last three to five years, the output of LED flashlights have made quantum leaps, to the point that any experience with using light for this purpose from more than five years ago may be irrelevant.
To be clear, I am referring to specifically to modern, high luminous intensity (20k candela and greater) flashlights that are now available. If someone is deprived of vision for a period of time after a dose of high-intensity light I would certainly refer to that as "incapacitation" in the context of being to fight effectively. So far the two examples cited seem to fit that definition.
According to another recent first-hand account using such a high-intensity light, a suspect remained combative, covered their eyes and charged in the direction of the light. That person was unable to attack effectively and was quickly subdued. Yes, the mindset of the suspect/assailant remained unchanged but their ability to deliver the attack was greatly impeded.
IMO, if the use of high-intensity light can impede or even prevent an attack, then its worth exploring.